I agree it is bizarre unless there is something more than has been said. The "its just not comfortable enough to play on" line isn't doing his rep for tooughness any good either. Nobody is ever 100% in the NBA.
But that said you just don't know how injuries respond, and this year in particular its ok for this to happen. If you're a 50+ win team trying to get over the hump, this sucks and could end up costing you by the end of the season. In our position an extra loss here or there is actually a good thing, as are the even younger guys getting minutes -- something our new coach doesn't seem anymore interested in than our old one. Put Kevin in the lineup, and Donte, JT and Brown may never see the floor again. So whatever. My eyebrows are raised at this point, but however much time he needs, he needs. The absolute worst thing you could do is have him come back early when it doesn't matter in the least, then have him develop something chronic. This year he can't help us do anything we need to do. But we will need him in the future.