Games are won on run differential -- scoring more than your opponent. Runs are runs, scored or prevented they all count the same. Worry about scoring more and allowing fewer, not which positions contribute to which side of the equation or how "consistent" you are at your current level of performance.
As far as I know, there's only 2 ways to send a player who's on the 40 man roster to the minors. One is by optioning him, which burns an option year unless the player spends less than 20 days in the minors all season. And the other would be to remove him from the 40 man roster, which isn't even worth mentioning because the player would have to clear waivers.
"Reality tells us there are no guarantees. Except that some day Jon Lester will be on that list of 100-game winners." - Peter Gammons
Found a nice primer at http://www.kffl.com/article.php/100555/236
I stand corrected.Options
* After three years as a pro, a player must be protected on a team's 40-man roster, or he is eligible for the Rule 5 draft.
* Once he's served those three years, and assuming he is added to the 40-man roster, his club then has what are called "options" on him.
* When a player is on the 40-man roster but not on the 25-man Major League roster, he can be "optioned out" - sent up and down - as many times as the club chooses within those three seasons.
* "Out of options" means a player has been in the minors in three different seasons. Beginning with his fourth as a pro, to be sent down again he has to clear waivers.