Proof? Here is an in dept study: Part 1 and Part 2. And here is a graph from the same source: http://www.hardballtimes.com/images/uploads/image003.png And if you like another metric, here is this table from here (short and sweet): Here’s the total WAR of ALL nonpitchers by age, of players born since Ruth’s birth year (1895): Age WAR 20 18 21 168 22 470 23 1,120 24 1,723 25 2,383 26 2,875 27 3,206 <-- 28 3,114 29 3,042 30 2,683 31 2,453 32 2,054 33 1,580 34 1,179 35 889 36 563 37 423 38 224 39 142 40 87 41 18 42 18 43 12 hope that the point is made (with data, not "gut feelings") Very select players decline slower, but 31-32 is the downside for all pretty much... Pitchers are slightly different beasts. Both of those are for position players. Why someone would sign declining players? Some teams do not do, other than in supporting roles. Ask Tampa. What people do, does not always make sense And does not make sense to keep players in the minors during their early peak years to gain service time for late peak and decline years...