Bills RB LeSean McCoy (hamstring) leaves practice

The Bills are exercising patience with running back LeSean McCoy.

Just days away from Buffalo's much-hyped matchup against the New England Patriots, McCoy left practice on Thursday with soreness in his hamstring.

"He just felt sore so we just backed him out of it," Bills coach Rex Ryan said after practice on Thursday.

McCoy's hamstring has hampered him since the preseason and he wasn't his normal self in the Bills' 27-14 Week 1 victory against the Colts. The running back rushed for a pedestrian 41 yards on 17 carries against Indianapolis.

Ryan is hopeful that Thursday's setback won't carry over into Sunday. Karlos Williams is No. 2 on Buffalo's depth chart and showed some explosiveness in Week 1, but Ryan knows he needs McCoy in the lineup against the reigning Super Bowl champs.

"I don't even want to think that way ... but like I said I'm not giving up on McCoy playing," Ryan said when asked if Williams might get the start in place of McCoy.

Hamstring injuries typically linger if not treated with rest and caution. It sounds like the Bills are taking the cautious approach with their prized offseason acquisition. Breathe easy Bills fans -- McCoy likely will play Sunday, but it would be premature to expect him at 100 percent.