PITTSFORD, NY — Two days into training camp, and the Buffalo Bills already have an injury to a key player that bears watching.

Defensive tackle Marcell Dareus, the highest-paid player on the team, tweaked his hamstring Friday afternoon and was sidelined for Saturday morning’s workout at St. John Fisher College.

"Any time players miss time, you get concerned, whether it's Marcell or anyone else," coach Sean McDermott said in his pre-practice briefing "I'm going to stay positive with it. He's done a great job of being in shape at this point in camp. Really handled things well. So, we'll see how this unfolds."

Dareus, the former No. 3 overall draft pick in 2011, has certainly given past coaching regimes headaches with his immaturity, run-ins with the law, and occasional poor conditioning which has led to injuries.