I thought it looked like he was cramping up a bit again. I have a suspicion that it's a young guy thing. Anyone remember a first game of anything? Maybe your first game in high school, first varsity game, first game in college, whatever; usually that first time you need to be on your horse, you labor through it, trying to force your body to move faster than it can. It leads to almost a cramping/stiffening feeling. A lot of guys get over it quickly, but it looks to me like Ameer still gets excited when he hits that open field and tries to push it instead of moving naturally. Watch his TD and the return he got hurt on, as soon as he hits open field it looks the exact same, the movement starts to look labored. That'll change pretty quick as he should be getting used to the game.