LeSean McCoy left practice early with a hamstring injury.
Bills coach Rex Ryan said Wednesday the running back's hamstring was tight and will be checked by the medical staff.
Ryan said he wasn't immediately sure of the severity of the injury.
"We'll see how it goes," Ryan said.
McCoy's injury history should force the Bills to be cautious with their star running back. Given the nature of soft-tissue strains, it will be important to track his progress the next two days of practice.
Shady has been the sparkplug behind Buffalo's four-game winning streak. McCoy is currently second in rushing yards in the NFL at 587. He's compiled six rushing scores and 5.6 yards per carry this season.
If McCoy's injury lingers, it would severely hinder the Bills' offense Sunday versus the Miami Dolphins. Mike Gillislee is currently the backup and would carry a larger load if McCoy's injury isn't a one-day affair. The drop off from McCoy to the No. 2, however, is severe.