It was his right ankle. He was a little gimpy coming off the field at some point in the third quarter, at which point RP replaced him. I remember seeing they'd wrapped it up in ice, so I don't know what the status is. Although he didn't look particularly perturbed about it.
He's such a team player, he probably faked it so his compadre could get more reps and a bigger stake in the glory of the Beamer Ball Busting.