05-07-2008, 07:10 PM
I don't know if you've read this or not, but it's very enlightening. Everyone I know that's read it has either changed their opinion on the matter or at least taken a serious look into it. Either way, it's a hell of a read. In regards to the injury posibilities...yeah, very limited data on that. But I certainly don't recall as many injuries back then as I see nowadays. But I'm no research expert. *shrugs*
part 1: http://www.baseballprospectus.com/article.php?articleid=1596
part 2: http://www.baseballprospectus.com/article.php?articleid=1605
part 3: http://www.baseballprospectus.com/article.php?articleid=1622
August 13, 2002
Doctoring The Numbers
The Five-Man Rotation
by Rany Jazayerli
The five-man rotation is a failure.
I don't mean to be overly dramatic here. I'm not trying to frame 'failure' in a pejorative sense, the way we might describe Tony Muser, or airport security pre-9/11, or Bud Selig's ceaseless efforts to acquire a human soul. I use the term "failure" in a purely literal sense. How else to describe a concept which has not succeeded in accomplishing the precise objective for which it was created?
The five-man rotation was a product of the early 1970s, when an era of free experimentation in our society leeched its way into baseball and a few teams dabbled in the concept, on the premise that it would keep their starting pitchers healthy. Most notable among these were the Dodgers, who made the switch midway through the 1971 season. In 1969, three Dodger pitchers (Claude Osteen, Don Sutton, and Bill Singer) each made 40 or 41 starts, providing just 37 leftover starts for the rest of the staff. By 1972, Sutton, Osteen, and Singer were joined by Al Downing and Tommy John, as all five pitchers started between 25 and 33 games, combining to start 150 of the Dodgers' 155 games. In retrospect, it's easy to understand why the Dodgers went with five starters - because unlike almost any other organization, they actually had five quality starters. How many teams can boast five starting pitchers whose names are still recognizable a quarter-century later?
The Dodgers' transition to a five-man rotation was not without its hiccups--they returned to using just four starters in 1974 and 1975--but it was ultimately irresistible. Since 1975, the Dodgers allowed a pitcher to make more than 35 starts in only one season, 1982. And during the 1970s, wherever the Dodgers tread, the rest of baseball was sure to soon follow. As ex-Dodgers and minor league managers trained in the Dodger Way promulgated their philosophy throughout baseball, the gospel of the five-man rotation was successfully spread to nearly every corner of the baseball map. By the early 1980s, only the Baltimore Orioles had not been successfully converted to the cause.
"It is easier to find four starting pitchers than five."
- Earl Weaver's Seventh Law. (From Weaver on Strategy, 1984)
In 1973, no less than twelve major league pitchers made 40 starts or more, the highest total of the 20th century. Following this trend year by year:
Year # of Pitchers >= 40 GS
(The 1987 outlier is Charlie Hough, a knuckleballer.)
Over the years, the concept of spreading starts out to as many pitchers as possible has been taken more and more literally. Once upon a time, the term "five-man rotation" meant that your best starters would throw every fifth day, and starters in the back of the rotation would be bumped when necessary to keep better pitchers on rotation. Today, teams are loathe to skip even their fifth starter, preferring to give their starters five or even six days of rest on occasion. The typical season runs around 180 days, meaning that an Opening Day starter working every fifth day, as opposed to every fifth game, should make at least 36 starts over a full season. A look at the number of pitchers making 36 or more starts in a season since 1973:
Year # of Pitchers >= 36 GS Year # of Pitchers >= 36 GS
1973 31 1985 14
1974 33 1986 10
1975 22 1987 11
1976 20 1988 4
1977 17 1989 7
1978 16 1990 2
1979 14 1991 4
1980 14 1992 2
1982 12 1993 5
1983 9 1996 2
1984 5 1998 1
Where have all those starts gone? To less-qualified pitchers, naturally. Whereas a generation ago, a team could expect to place 80% of its starts in the hands of its four best starting pitchers, today that percentage is far less.
Compare the status of major league rotations in 1973 compared to 1999. The following chart lists the average number of starts made by each slot in the rotation:
Slot 1973 1999 Diff 1973 1999 Diff
1 37.3 33.2 -4.1 37.3 33.2 -4.1
2 34.1 30.7 -3.4 71.4 63.9 -7.5
3 29.6 28.3 -1.3 101.0 92.2 -8.8
4 23.2 23.6 +0.4 124.2 115.8 -8.4
5 14.9 17.9 +3.0 139.1 133.7 -5.4
6+ 22.8 28.2 +5.4 161.9 161.9 0
(The cumulative numbers add up to only 161.9 because of a few rainouts.)
What this chart tells us is that the average "ace" starter made 37.3 starts in 1973, but only 33.2 starts in 1999 - a dropoff of 4.1 starts. Number two starters lost almost as many starts (3.4), and #3 starters lost 1.3 starts apiece. Those 8.8 starts have been redistributed to far less qualified pitchers. A miniscule number went to #4 starters, but the vast majority have gone to pitchers ranked 5th or worse on a team's depth chart.
That's nearly 9 additional starts - 7.5 of which came from the two best starters on a team - that have been redistributed to fifth starters, spot starters, long relievers, and emergency call-ups. That's a pretty steep price to pay for the luxury of a five-man rotation.
"I expect the real reason baseball will eventually return to the four-man rotation will be the simplest of all: It helps win games. The five-man rotation is not on that evolutionary path; it's a digression, a dead-end alley. Just as baseball once believed that walking a lot of batters was better than throwing a home-run pitch, we are now chasing an illusion that our pitchers work better on four days' rest and that the five-man rotation significantly improves their future."
- Craig Wright, in The Diamond Appraised, 1989.
As Wright points out, the crux of the entire argument for the five-man rotation is that it keeps pitchers healthier. Which makes the crux of my argument this: the five-man rotation does NOT keep starters any healthier than the four-man rotation. And if it doesn't provide any health benefits, what benefit is there?
Between 1973 and 1975, 68 pitchers made between 37 and 43 starts, roughly conforming to expectations in a four-man rotation. Coincidentally, between 1991 and 1993 exactly 68 pitchers made between 34 and 35 starts, the high end of expectations for starters in a five-man rotation. Let's compare the two groups:
Group G GS CG ShO W L Pct IP H HR BB K ERA
Four-Man 2676 2642 1088 226 1230 973 .558 19341 18005 1522 6123 11494 3.31
Five-Man 2343 2335 368 101 1040 771 .574 15960 14874 1313 4784 10527 3.51
In terms of quality, the two groups are very similar. The guys in the five-man rotation had a slightly higher winning percentage (but fewer decisions per start). They had an ERA 20 points higher than the earlier group; since the average major league ERA from 1973 to 1975 was 3.69, and the average major league ERA from 1991 to 1993 was 3.94, the relative ERA of the five-man group was about 5 points lower than that of the four-man group.
The average age of the guys in the five-man rotation was 29.2 years old; the guys in the four-man rotation were 29.4 years old.
While the two groups are of comparable quality, their value--owing to the increased use of the pitchers in the four-man rotation--is not comparable. The earlier group averaged more starts (38.9 vs. 34.3) and more innings (284.4 vs. 234.7) than the latter group. Fifty additional innings are a tremendous commodity - remember, we're talking about the best starters in the league here.
Here's the kicker: all those extra starts, and all those extra innings, did NOT cause any long-term damage to those pitchers. If you take the same group of pitchers and examine their performance 5 years later, here's what you find:
Group G GS CG ShO W L Pct IP H HR BB K ERA
Four-Man 1562 1236 342 75 545 431 .558 8968 8666 756 2940 5200 3.58
Five-Man 1476 1351 121 36 538 473 .532 8722 9010 916 2857 6677 4.31
Five years later, 50 of the 68 pitchers in the original four-man group were still active, compared to 54 of the 68 pitchers in the original five-man group. The most likely explanation for the discrepancy is simply age; while the average age of the two original groups was similar, 9 of the 68 pitchers in the earlier group were 35 and older; only 5 of the 68 pitchers in the later group were.
But even with four fewer members to count, the earlier group was still going as strong, if not stronger, five years later. The surviving members of the four-man group made fewer starts, but pitched in more games, and threw more innings than the five-man group. (They did suffer a greater percentage drop in their innings, but keep in mind a big reason for that is that in the ensuing five years, many of their teams switched from a four-man to a five-man rotation.)
Their winning percentage, which was 16 points lower than their counterparts in the original study, is now 26 points higher. Their combined ERA is 24 points better than league average (3.82), while the pitchers in the five-man group had an ERA only 17 points better than league average (4.48). This is also a reversal from five years prior; while the original four-man group had a relative ERA 5 points worse than the five-man group, the same group now has an ERA 7 points better.
The last paragraph is a little confusing, so let's put that in chart form:
Year 0 Year 5 Year 0 Year 5
Group Win Pct Win Pct Diff Rel ERA Rel ERA Diff
Four-Man .558 .558 .000 -0.38 -0.24 +0.14
Five-Man .574 .532 -.042 -0.43 -0.17 +0.26
Rel ERA = Relative ERA
Five years after our study, the pitchers in a four-man rotation had the exact same winning percentage, and a relative ERA only 14 points higher than before. By comparison, the pitchers in a five-man rotation saw their winning percentage drop 42 points, and their ERA rise by nearly twice the margin of the four-man group.
Bottom line: if these numbers suggest anything, it's that pitching in a four-man rotation is less damaging than pitching in a five-man rotation. Now, the difference between the two groups isn't enormous, and neither is the sample size, so I'll concede the point that these differences are not statistically significant. I'm not trying to argue that working on three days' rest is more healthy than working on four days' rest, only that it isn't less healthy. Given the obvious tactical benefits that come from taking innings away from the worst pitchers on your staff and giving them to your best, shouldn't that be enough?
Next week, I'll address the apparent paradox: if limiting pitch counts is such a good idea because it reduces the risk of pitcher injury, how can it also be a good idea to increase pitch totals by increasing the number of starts a pitcher makes?
August 20, 2002
Doctoring The Numbers
The Five-Man Rotation, Part 2
by Rany Jazayerli
Today, we'll pick up last week's discussion where we left off. (Take a look at last week's article if you haven't already.)
To answer the question I ended last week's column with, it is very important to understand that my support of the four-man rotation is not, in any way, mutually exclusive with my belief in the importance of limiting pitch counts. It is fairly well-established (albeit not as well as I would like) that high pitch counts increase the risk of pitcher injury. But it does not follow that starting on three days' rest is more dangerous than starting on four days' rest. This is not a paradox at all, as both phenomena can be explained by one simple principle, which is important enough that it ought to be named and capitalized. Let's call it the Principle of Pitcher Fatigue:
Throwing is not dangerous to a pitcher's arm. Throwing while tired is dangerous to a pitcher's arm.
A gathering body of orthopedic evidence suggests that pitchers lose their mechanics as they become fatigued, and it is those imperfect mechanics that put undue strain on the arm, ultimately leading to injury. This is why a single 150-pitch outing can be more dangerous than a dozen 100-pitch outings. This explains why the PAP3 system works.
But this also explains why working on three days' rest may not be any more dangerous than working on four days' rest, because there is no evidence - absolutely none - that a pitcher needs a fourth day off to reach a maximum state of rest. I've searched the medical literature for any study that measures a pitchers' resting strength following a start, and such a study doesn't exist. No one has gotten around to measuring whether, to return to full strength, a starting pitcher ought to rest his arm for 3 days, or for 3 hours, or for 3 weeks. The move to a five-man rotation is simply not based on hard medical evidence.
Does a reliever need four days of rest? Of course not. Jesse Orosco has been pitching every other day since a Beatles reunion was still possible. If more rest were always beneficial, then it would follow that five days of rest is even better than four. No one believes, that, of course, which is why no team has ever seriously flirted with a six-man rotation.
Certainly, every pitcher is constructed differently, and it's possible that even four days of rest isn't enough for some pitchers. For decades prior to the standardization of regular pitching rotations, teams would routinely give veteran pitchers five or six days of rest. The tradition of the "Sunday starter" culminated when the Chicago White Sox gave Hall of Famer Ted Lyons, then 41 years old, twenty starts in 1942. Lyons completed all 20 starts, went 14-6, and led the league with a 2.10 ERA.
The practice of giving certain pitchers additional rest is complicated by having to keep other pitchers on rotation, but occasionally the situation warrants it--for example, with Pedro Martinez. From 1999 through last year, the Red Sox tried their damndest to give him five days of rest when they could. Pedro is not a large man at 5'11", 170 pounds, and the Red Sox were tacitly admitting that Pedro's small stature meant that they had to personalize their care of him to account for his particular situation.
Their method didn't keep Pedro from breaking down, though, because the Red Sox continued to let him throw 120 or 130 pitches when he did start. Despite making only 29 starts in both 1999 and 2000, Martinez eventually wilted from the abuse and missed half of 2001. Upon his return this year, the Red Sox have not only given him as much rest as possible, they've also limited his pitch counts--he hasn't thrown more than 117 pitches all season. After a spring in which it looked like he would never return to his dominant form, Pedro has only gotten stronger as the season has gone on.
The example of Martinez not only illustrates the limitations of additional rest, it also points out the importance of integrating a move to the four-man rotation into a comprehensive philosophy on monitoring pitcher workloads. The last time a team seriously experimented with the four-man rotation was in 1995, when Bob Boone went with four starters for the first half of the season. After getting off to a rousing start--Kevin Appier began the year 11-2 with a 1.89 ERA--the trial was scrapped after Appier and Chris Haney suffered arm problems. The downfall of the experiment was that Boone did not compensate for his starters' decreased rest by limiting their pitch counts. On the contrary; Appier threw 141 pitches in a start shortly before he went into the tank.
I am confident that the organization that is willing to return to the four-man rotation, in conjunction with strictly monitoring their starters' pitch counts, will gain tangible benefits without increased risk to their pitchers.
There is another substantial benefit that comes from the four-man rotation, which is that pitchers have better command on three days' rest. Almost every pitching coach--and most pitchers that have tried--will tell you that when you pitch on three days' rest, your stuff is a little sharper, and has a little more sink.
This sounds like mere anecdotal evidence, but in this case the anecdotes are fortified by the statistical data at hand. With the help of Keith Woolner and the wonderful people at Retrosheet, I was able to obtain start-by-start data for all pitchers back to 1978. In the past 24 years, no less than 160 pitchers have made at least 8 starts in a season on both three and four days' rest. By looking at how their performance on varying amounts of rest, we can determine whether being brought back one day earlier had any deleterious effects.
The combined numbers of those 160 starters:
Rest IP H ER BB K HR ERA H/9 BB/9 K/9 HR/9
3 days 13666 12986 5428 4270 7516 1087 3.57 8.55 2.81 4.95 0.72
4 days 16082 15658 6882 5063 9052 1389 3.85 8.76 2.83 5.07 0.78
Did the pitchers suffer from being afforded less rest? Hardly. They pitched better on shorter rest, with an ERA over a quarter run lower. In a combined sample size of nearly 30,000 innings, that's significant. 92 of the 160 pitchers (58%) had lower ERAs on three days' rest. Even if we lower the threshold to include all pitchers who made even 5 starts on both three and four days' rest (368 pitchers in total), the numbers don't change: 215 of the 368 (58%) had lower ERAs on three days' rest.
A closer breakdown of their performance lends credence to the idea that pitchers have better command, and more sink, on three days' rest. With less rest, the starters let their defense work for them, with fewer walks and fewer strikeouts. But perhaps the most relevant effect is that they allowed nearly 10% fewer home runs per inning.
It's not unequivocally clear that starters perform better on three days' rest than on four. But it is crystal clear that they don't perform any worse.
A lot has been made of the recent struggles of pitchers who were asked to return on three days rest. In 1999, Darryl Kile and Pedro Astacio each made five starts on short rest, and Kile had a 7.39 ERA, Astacio 9.83. However, their performances should not imply that pitchers today have more trouble coming back on three days' rest than pitchers of 20 years ago. The last starters to make at least 8 starts on short rest did so in 1995, when a trio of Royals (Appier, Mark Gubicza, and Tom Gordon) and a pair of Pirates (Denny Neagle and Esteban Loaiza) were called upon a combined 47 times on three days' rest. Their performance that season:
Rest IP H ER BB K HR ERA H/9 BB/9 K/9 HR/9
3 days 302 310 131 90 214 23 3.90 9.23 2.68 6.37 0.68
4 days 541 561 250 184 325 58 4.16 9.33 3.06 5.40 0.96
The sample size is extremely small, but the performance of this group from just seven years ago ought to squelch any talk that pitchers today simply can't come back on short rest the way pitchers of previous generations could.
Another issue that is frequently raised regarding the four-man rotation is that it would be difficult to expect pitchers in mid-career, who have been trained to pitch on four days rest their whole lives, to suddenly change their work habits.
Hogwash. At the beginning of spring training, few teams have settled on their fifth starter, and most teams put the established members of their rotation on the mound every fourth day, beginning with long-toss sessions before exhibition games have started, continuing with 2-3 inning outings in early March, and progressively lengthening them, before finally switching to outings every fifth day in the final few weeks of the spring. Keeping those pitchers on an every-fourth-day regimen would not require a change in their training habits. On the contrary, it's switching to an every-fifth-day cycle that requires an adjustment.
That's the smaller point. The bigger point is this: if pitchers really had difficulty adjusting from having to pitch every fifth day to pitching every fourth day, wouldn't they have even more difficulty switching from starting to relieving? John Smoltz had been starting in a five-man rotation for over a dozen years before he was moved to the bullpen, and he's taken to the closer role like a fish to water. Eric Gagne has been a starter throughout his pro career--did he struggle when moved to the bullpen? Of course not. Neither did Mariano Rivera, or Billy Wagner, or Billy Koch, or dozens of other pitchers who started their entire careers before they were moved to the bullpen and found immediate success.
Starters throw to full exertion, on a regular schedule, with plenty of notice before their next appearance. Relievers throw in short stints, may pitch in three straight games or not pitch for ten days straight, and don't know if they're going to pitch on any given night until five minutes before they're brought in. You couldn't create two roles that required more different physical and mental preparation--and yet pitchers go back and forth between the two all the time. Yet we're supposed to believe that a starter can't adjust to a usage pattern where he 1) stays on a regular schedule and 2) still knows in advance when he's going to pitch, just because he gets a different amount of rest? Please.
Next week, we'll wrap up this topic by looking at the other, ancillary benefits of the four-man rotation.
August 30, 2002
Doctoring The Numbers
The Five-Man Rotation, Part 3
by Rany Jazayerli
To wrap up our series on the merits of the four-man rotation, let's look at some of the ancillary benefits of making the switch:
1. The four-man rotation simplifies a starter's between-start schedule. Most teams have their starters throw on the side once between starts, but no one really knows whether it's better to throw on the second day after a start, or the third. It's not even clear whether starters should throw only once. In Atlanta, Leo Mazzone has had continued success doing things his way: he has his starters throw twice on the side between starts instead of once. (He does this because he feels it gives the starter the same increased sharpness that comes from working on three days' rest.)
In a four-man rotation, there is no dilemma. A starter rests on day 1 after a start, throws on the side on day 2, rests on day 3, and is back on the mound on day 4.
2. If you need fewer starters, you need fewer pitchers, period. Moving the fifth starter to the bullpen gives a team the luxury of having a long reliever who can take the pressure off the other relievers, three and four innings at a time. A team that carried six relievers would only need ten pitchers - you know, the way they did things back in the 80s. Even if a team needed to carry around a seventh reliever as a crutch, they would only require 11 pitchers. By carrying one fewer pitcher, a team would open up an additional roster spot for a pinch-hitter, or a pinch-runner, or a defensive replacement. Plus, in the National League, teams that go to a four-man rotation and pull their starters earlier in the game would increase the number of the pinch-hitting opportunities, thereby slightly improving their offense.
Earl Weaver never carried more than 10 pitchers at a time, and frequently kept just 9. In so doing, he was able to carry as many as seven bench players, allowing him to mix and match talented role players like John Lowenstein and Terry Crowley and Benny Ayala. He was able to start a defensive whiz like Mark Belanger at shortstop because he had enough bullets on his bench to pinch-hit for Belanger if the Orioles were losing late, and have the defensive replacement on hand as well.
Today, some teams carry as many as 13 pitchers at a time, leaving room for just four bench players in the NL, three in the AL - one of whom has to be a backup catcher. This hamstrings a team's in-game flexibility, limits tactical options late in the game, and provides little depth to weather injuries.
Switching to a four-man rotation is a move designed to benefit the pitching staff, but it helps the offense as well.
3. Your best pitchers not only throw more innings, they throw more relevant innings. Working in a five-man rotation where they are limited to 33 or 34 starts, the only way most starters can reach 220 or 230 innings in a season is to throw a good number of innings in games that are already in hand. Just looking at games from this past weekend: Freddy Garcia tossed the 7th and 8th innings of a game the Mariners were leading 12-4; Jason Schmidt pitched the 7th inning with the Giants leading 7-2; Randy Johnson tossed the 9th inning with the Diamondbacks leading 7-0; Tim Hudson pitched a complete game even though the A's were ahead 11-3 after 3 innings.
Three of these four pitchers are among the best starters in the game, and Schmidt is no slouch. All but Schmidt are on pace to throw over 220 innings this year. But as these examples show, some of those innings are being used in low-leverage situations that provide little benefit to their team, because any major-league pitcher worthy of a roster spot should be able to protect a five-run lead with two innings to go.
By giving starting pitchers an additional seven or eight starts per year, you guarantee that those innings will have meaning; after all, every game starts with a tie score. With more opportunities to pitch, there is less need for a starter to accumulate innings by working deep into ballgames where he has a comfortable lead, allowing the less-experienced pitchers on the staff the opportunity to get some innings in low-pressure situations.
4. More regular work may help young pitchers develop more quickly. We're talking about the great unknown here, but isn't it possible that young pitchers may be even fresher on three days' rest than veterans? Examples of great starters who required extra rest as they approached 40 are myriad, with the most recent example being David Cone. You rarely hear of the 21-year-old fireballer that needs an extra day of rest, though.
The dilemma of how to best develop pitchers while keeping them healthy has been vexing baseball teams for decades. Because the minor league season only runs through Labor Day, there are fewer innings to distribute among minor league prospects. As every organization wants its best prospects to get as much repetition as possible, with only 26 or 27 starts available, the only solution has been to allow those prospects to pitch 6 or 7 innings a start. For a 22- or 23-year-old major league starter, that workload is dangerous; for a 20-year-old prospect in A-ball, it borders on criminal negligence.
We have already seen at least one influential baseball man, Grady Fuson, take a different tack. In order to get his charges as much work as possible while keeping them healthy, Fuson has experimented with a modified version of the four-man rotation. In his system, eight pitchers are split into four pairs, working every fourth game, with one member of the pair starting, and the other relieving after the starter has reached a very conservative pitch limit, somewhere around 80 pitches. The two pitchers then switch places the next time through the rotation. Two or three pitchers are made permanent relievers to fill in the gaps along the way.
Fuson has hit upon something very important: based on the existing research, it seems safer to allow young pitchers to work on less rest than to allow them to throw 110 or more pitches in a game. The organization that decides to switch to a four-man rotation can start at the minor league level, either by using the Fuson formula or simply going with the traditional four-man rotation, as long as those starters are placed on very strict pitch counts. With 33 or 34 starts in a minor league season instead of 26 or 27, those starters won't have to pitch 6 or 7 innings a start to get their innings in. Even averaging only 5 innings per start, a minor league pitcher in a four-man rotation could throw 165 or 170 innings a season, which is as much as most minor league starters rack up today.
The days of the five-man rotation are numbered. Baseball strategies are governed by the same evolutionary processes that guide strategies in any business: those that are successful are kept, while those that are not are discarded. Major League organizations are learning that the best way to keep their pitchers healthy is to restrict their pitch counts. Eventually, some bright guy in a major league front office is going to realize that if the solution to keeping pitchers healthy is to limit their pitch counts, maybe limiting their starts isn't part of the solution at all.
And once that light bulb goes on, the only thing that will keep teams from experimenting with the four-man rotation will be inertia, that pervasive tendency among baseball teams to keep from rocking the boat and putting their ass on the line. Don't discount that inertia, for it is a powerful thing - but eventually, it will be overcome.
At some point in the next five years, I am confident that we will see the return of the four-man rotation. It might come from the Reds, who have a manager that's proven he's ballsy enough to try the maneuver, a GM who is willing to consider anything that might make his team better, and a pitching coach who's worked wonders building starting staffs out of spare parts. It might come from another team, one that is both creative and desperate enough to clear away the mothballs from a concept that worked well 30 years ago, and can still work well today.
The four-man rotation is poised to make a comeback. As far as I'm concerned, it can't come back soon enough.
Rany Jazayerli is an author of Baseball Prospectus. You can contact him by clicking here.
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