Tough break for the kid, sounds like he was making some big strides...
Linky
I replayed the game and saw the injury. It was on the kickoff after the first touchdown, I believe. Barnes, of all people, got pancaked by the guy he was trying to block and fell backwards onto Schouman's ankle. At first I thought he either broke his fibula or sustained a dreaded "high ankle sprain", but Chris Brown seems to indicate it's his knee. Probably strained it pretty bad.
My guess is it's a 4- to 6-weeker. Maybe see him by Week 3 or 4.