He was limping a bit on the last series that he was in on Saturday, guessing he's got an ongoing/nagging issue with his left(?) knee. Looked like the coaches saw it, ran the ball the rest of the series, punted and took him out. (I'm just guessing that's what they did since that's what it looked like, don't actually know though.) They kept him in one series too long on Saturday.
My guess is he'll be 100% ready to go each week but it's going to be something that doesn't go away any time soon.. either way like the prior poster said, he's on fire throwing the ball, so I'm hoping we don't run him too much at all unless totally necessary.