Re: MLB 2011 Part 1
Well, what David Ortiz thinks is neither here nor there. Posada is, what, 39 now? 39 year old catchers (even though he's a DH now) are like 44 year old position players. It's the position that wears out the man, and at that particular position, when a player starts to slip, it's nearly always irreversible. It's the position, not the player. Hell, Johnny Bench started his decline at age 29. And no, I'm not touching the PED conversation here with a 10-foot-pole.
Rob Neyer wrote a nice piece a few years ago about how quickly catchers decline and wear down, and I wish I still had access to it. He analyzed virtually every good catcher in the last 70 years or so, and concluded that more or less, the threshhold for catchers is either age 32 or 1500 games caught. After that the production dropped off dramatically. While that doesn't necessarily hold true for Posada, the closest peer he has, both in age and recent production, is Ivan Rodriguez. People can sit here and say, "well, Pudge is still catching everyday. What's the problem?", but they're not paying attention to his production over the last 5 years.
Pudge's career totals, year by year
You could easily argue that he has been in decline since 2004, looking at his SLG, his homers and RBI. His slugging % has declined every single year since 2004. His punch at the plate is gone, and his ability to get on base is down as well, due mostly to his laughable walk totals the past few years.
Enough about Pudge. Back to Jorge. You can argue that he's been in decline since a fabulous 2007 season, where he hit .338-20-90. Throwing out the 2008 season due to injury (admittedly dangerous since he was a 37 year old catcher at the time), his AVG, OBP, and SLG have also declined every year since '07. All signs point to him being done after this season, or sooner, regardless of contract status.
Posada's lifetime stats
P.S. Oh, and Twins fans? You can go ahead and use this any way you wish with regards to your catching situation as well.