"Aging Process Strikes Again" by Doug Glanville - ESPN.com

With Jeter and Posada getting older, and a changing of the guard taking place with the Yankees, much has been made about old players and when they should hang 'em up. Doug Glanville--a former pro ballplayer himself--writes an insightful and kind of heartbreaking article here about realizing that you've lost a step, and you're never going to get it back. He makes the interesting observation that "baseball players are terrible self-evaluators who need denial as much as they need a rocket arm." He's right. In a sport where failing 70% of the time is considered a good thing, you better have a short memory, be an optimist, and have mental toughness. If you don't, I'm sure it's not to late to try out for lacrosse. Bunch of little league drop-outs over there. Couldn't hit a curveball.

http://sports.espn.go.com/mlb/columns/story?columnist=glanville_doug&id=6547213