Gailey said Thursday that Barnett's sore knee is not healing as quickly as expected. But, Gailey added, he has no reservations of Barnett playing on Sunday, when the Bills (5-8) "host" the Seahawks (8-5) at Toronto.
Barnett has not missed a game this season, and it's unclear when he was hurt.
Defensive end Mark Anderson has a chance to play for the first time since having surgery on his left knee, which he hurt in a 45-3 loss at San Francisco on Oct. 7.
Gailey says he was encouraged by Anderson's progress after he practiced for a second straight day.