you could say the fact that he plays every day (or did before Baltimore) wears him down.  Same thing with Matsui asking if he could do "extra work" on top of his team workouts.

Maybe it keeps Tejada sharp (although we haven't seen that this spring.)

Or maybe he's just trying to get back to where he was before the injured arm/hand/wrist in Baltimore.

It seems to me that things like that should be treated on a case by case basis.  He probably should play less in the offseason now that he's getting older... but maybe Tejada is just one of those players (and it seems to me that he is) that just loves playing baseball so much that he'd do it even if he didn't get paid millions of dollars.

1 stint on the DL and it wasn't because his body is being worn out.  I doubt winterball is hurting him.  Like Tex said, it might be an issue in the future as he gets older, but I don't see it being an issue.  

if the Astros tried to prevent him from playing winter ball. This is something which is very important to him, which is why he has done it every off-season since he began playing professional baseball.  I recall that, when the Orioles were shopping Tejada over the last couple of years, reportedly he told the Orioles that any new team had to approval his winter ball as a condition of Tejada accepting the trade. I have no idea how the winter ball affects him physically, but it doesn't seem like it's worth changing something which is that important to him.