Before hitting the practice fields at St. John Fisher University on Sunday morning, Buffalo Bills head coach Sean McDermott spent several minutes running through a lengthy list of injured players. It’s a list that includes two who are listed as week-to-week: cornerback Maxwell Hairston, who’s now joined by wide receiver Khalil Shakir.

Buffalo Bills' running back James Cook did not take part in practice with the team on Sunday. Here's what we know about his absence from the latest session of training camp.

It’s unknown what exactly changed since Cook part participated in the team’s Return of the Blue & Red scrimmage on Friday night, but a lack of progress in contract talks could be why the back is suddenly having a hold-in of sorts at Bills training camp.