View Full Version : OPS+ (adjusted to player's ballpark)

07-07-2009, 06:31 PM
From baseball-reference.com:

Adjusted OPS+
This value is calculated differently from the Total Baseball PRO+ statistic. I chose OPS+ to make this difference more clear. PRO+ as best I can tell is

OPS+ = PRO+ = 100 * ( OBP/lgOBP + SLG/lgSLG - 1)/BPF

Where lgOBP and lgSLG are the slugging and on-base percentage of a league-average player, and BPF is the batting park factor. This takes into account the difference in runs scored in a team's home and road games, so it doesn't depend on how good an offense or defense a team has.

My method is slightly more complicated, but I think it is more correct. The BPF is set up for runs and the way it is implemented in PRO+ applies it to something other than runs.

My method:

Compute the runs created for the league with pitchers removed (basic form) RC = (H + BB + HBP)*(TB)/(AB + BB + HBP + SF)

Adjust this by the park factor RC' = RC*BPF

Assume that if hits increase in a park, that BB, HBP, TB increase at the some proportion.

Assume that Outs = AB - H (more or less) do not change at all as outs are finite.

Compute the number of H, BB, HBP, TB needed to produce RC', involves the quadratic formula. The idea for this came from the Willie Davis player comment in the Bill James New Historical Baseball Abstract. I think some others, including Clay Davenport have done some similar things.

Using these adjusted values compute what the league average player would have hit lgOBP*, lgSLG* in a park.

Take OPS+ = 100 * (OBP/lgOBP* + SLG/lgSLG* - 1)

Note, in my database, I don't store lgSLG, but store lgTB and similarly for lgOBP and lg(Times on Base), this makes calculation of career OPS+ much easier.

Here are your current REDS w/ their Age, Plate Appearances and their OPS+. I included age because hitters get worse as they get past 28 and get better as they approach 27:

Age; Plate Appearances; OPS+

Wilkin Castillo: 25; 3; 251
Joey Votto: 25; 209; 175
Jonny Gomes: 28; 93; 165
Micah Owings: 26; 44; 122
Ryan Hanigan: 28; 163; 117
Laynce Nix: 28; 186; 105
Brandon Phillips: 28; 319; 104
Chris Dickerson: 27; 209; 102
Jay Bruce; 22; 323; 93
Jerry Hairston; 33; 278; 86
Ramon Hernandez; 33; 291; 82
Danny Richar; 26; 9; 56
Willy Taveras; 27; 293; 55
Paul Janish; 26; 82; 53
Adam Rosales; 26; 149; 48
Alex Gonzalez; 32; 198; 46
Matt Maloney; 25; 5; 32
Darnell McDonald; 30; 44; 26
Edwin Encarnacion; 26; 89; 26

Here's each players' OPS+ for the last 5 seasons (along w/ Plate Appearances) so you can see their trends. Obviously, the younger players aren't going to have 5 years of OPS+ ratings in the Majors. Wilkin Castillo w/ 3 PA's in 2009 is not realistic, but others have a lot of at-bats to see a trend. I'll leave the current ages so you can see what their ages were for the seasons. All of this assumes no steroids, too. So, if Hairston or Hernandez or some of these other veterans were using steroids before the recent crackdown, then this year's numbers would reflect also a sharp decline. I used one extra year for Nix because he had PA's in consecutive years of 70, 12, & 13, but 400 two years before the 70. Alex Gonzales has no record for '08, and when you're older and don't play for more than a year, you decline even faster.

Age; (PA/OPS+) for each of last 5 years w/ 2009 being the last year shown:

Wilkin Castillo: 25; (34;60), (3;251)
Joey Votto: 25; (89;127), (589;124), (209;175)
Jonny Gomes: 28; (407;139), (461;95), (394;105), (177;73), (93;165)
Micah Owings: 26; (64;153), (62;97), (44;122)
Ryan Hanigan: 28; (11;95), (98;91), (163;117)
Laynce Nix: 28; (400;81), (240;70), (70;8), (12;-100), (13;-35), (186;105)
Brandon Phillips: 28; (9;-100), (587;88), (702;105), (609;92), (319;104)
Chris Dickerson: 27; (122;160), (209;102)
Jay Bruce: 22; (452;96), (323;93)
Jerry Hairston: 33; (430;82), (192;36), (184;42), (297;124), (278;86)
Ramon Hernandez: 33; (392;107), (560;111), (409;88), (507;86), (291;82)
Danny Richar: 26; (206;78), (37;29), (9;56)
Willy Taveras: 27; (635;75), (587;74), (408;89), (538;56), (293;55)
Paul Janish: 26; (89;36), (82;53)
Adam Rosales: 26; (30;23), (149;48)
Alex Gonzalez: 32; (478;85), (429;75), (430;99), (00;0), (198;46)
Darnell McDonald: 30; (00;0), (00;0), (11;-21), (00;0), (44;26)
Edwin Encarnacion: 26; (234;93), (463;108), (556;101), (582;106), (89;26)
Drew Sutton: 26; (4;-100)

A hitter's biggest improvements from one year to the next in their careers are their 27th and 28th years. Their largest declines are in their 30th and 31st years. This information comes from Bill James analyzing every person that's ever played a Major League game. Again, steroids changes everything.

But, looking at this, it's not a surprise that Dickerson, Hanigan, Gomes, Nix, and Phillips are having their best years. Taveras, as you can see, has never been any good, and he is just as bad this year as he was last year with no improvement whatsoever. With his age, it was a calculated gamble by Walt that he'd get back to what he did before 2008. Usually that would be a good bet, but you can't win them all. He hit it with Gomes and Nix are right where you could expect them to be, though Gomes should come back down a bit the second half and finish closer to 120, a number that fits right into his 2007-2007 seasons. Dickerson's a good player right now. Hanigan's a good player right now. There's no reason to think they'll be better next year or the year after as they head into their declining physical condition. EE's as consistent as they come. Because he got off to such a bad start, he probably won't finish the year between 100 and 108, something you could have counted on before the season began, but he could easily finish around 85 as he could have an OPS+ of 105 the rest of the way. Bruce is young. Those 92-93's are going to be jumping 20 points each of the next 4 years, 113 in 2010, 133 in 2011, 153 in 2012, and 173 in 2013. Or, something like that. Ramon Hernandez and Jerry Hairston are old. They are doing this year exactly what was expected of them. Their declines are well documented in the OPS+. But, still, they aren't bad numbers for their positions. Low '80's for a Catcher is tolerable, but not when you have another Catcher at 117, and his two previous seasons were in the low-90's. This isn't some fluke with Hanigan. He'll finish the year exactly where he is no matter how many at-bats Dusty gives him. He's a 117 OPS+ hitter this year. Hernandez is an 82-85 hitter. That makes Hanigan about 40% better Offensively doing the math.

No player with an expected OPS+ in the '80's should start unless he's a Catcher, and a decent one at that, or an outstanding SS defensively. Hairston is neither, and belongs on the bench, with only an occasional spot-start. Oh, yeah, Owings is a good-hitting pitcher....and he's only 26.