Stacy returned a kickoff 9 yards as time expired in the first half Thursday night and was tackled by Jonathan Meeks. As the teams jogged off the field to head to their locker rooms, Stacy remained down and clutching at his left leg.
Team doctors ran onto the field to attend to Stacy and worked on his left ankle for a few minutes before helping him onto a cart and into the locker room.
Stacy was returning the kickoff after Devin Smith fumbled one earlier in the quarter that Duke Williams returned 19 yards for a touchdown for the Bills.
Bills defensive end Mario Williams was questionable to return with an illness. He hadn't played since early in the game.