Buffalo Bills running back LeSean McCoy is listed as questionable for Sunday's game against the New England Patriots.
McCoy, who was unable to finish Thursday's practice after developing tightness and soreness in his hamstring, was limited during Friday's session at Ralph Wilson Stadium.
"It is kind of tricky to gauge it and things like that," Ryan said of the running back's injury. "But a little bit of a concern."
Safety Corey Graham, who suffered a concussion in last Sunday's season-opening victory against Indianapolis, fully participated in Friday's practice. He's listed as probable for the New England game, along with wide receiver Percy Harvin (hip).
Ryan said Graham passed all of the tests in the NFL's concussion protocol and is "ready to go."
Wide receiver Marquise Goodwin (ribs) and linebacker Tony Steward (knee) are out for Sunday. In the early portion of practice open to the media, both were seen doing some work off to the side.
"They're getting a lot better," Ryan said. "The one kid" Goodwin "had his shirt off; he's trying to look good. 'McRib,' I think they call him. But he's doing better and Steward's coming along, too, so it shouldn't be long for these guys."