M's Beltre playing in pain

Why are Adrian Beltre's hitting stats so crummy? As Larry LaRue writes, Beltre is hurting:

    Beltre Adrian Beltre's immediate future with the Seattle Mariners is totally dependent upon how much pain he can play in -- the bone spurs that forced surgery a year ago have returned in his left shoulder.
    "It's the same thing I had last year, bone spurs, only it's worse. I had x-rays yesterday and they've grown back, in the same place," Beltre said today. "I think they're worse this year.

    "I'm going to need surgery, now or later. It's a matter of how long I can play with the pain."

Beltre's hitting stats are his worst since 1998, when he was a 19-year-old rookie. His walks are way down, his power way off. This might seem like one of those situations where you admire the player for playing, but question the team's wisdom in letting him play.
Or not. As usual, Beltre's defensive numbers are outstanding; he might well deserve another Gold Glove if he's able to play for most of the season. And the M's have nobody capable of replacing him. On the major league roster, they could slide Russ Branyan to third base and install Mike Carp at first base, except Branyan's an awful third baseman and Carp's a born DH. In Triple-A, their third baseman is Chris Shelton (remember him?), who's been pounding the ol' horsehide but is probably worse at third than Branyan.

So as bad as Beltre's been, he should probably keep his job unless he gets even worse or the Mariners can pull off a trade for a real third baseman (and remember, they're only two-and-a-half games out of first place).