ORCHARD PARK, N.Y. (AP) -- Bills quarterback Thad Lewis is doubtful for Sunday's game against the Kansas City Chiefs due to a rib injury.
Lewis returned to practice on Friday on a limited basis. He participated in drop backs with his fellow quarterbacks during the portion of practice open to the media but did not throw any passes.
''It's a point of the soreness of the ribs, really just being able to turn and throw and that's the one thing that's holding him back,'' Bills coach Doug Marrone said. ''If he can get by that, then he'll be able to play.''
Lewis has started the last three games at QB for Buffalo in place of injured starter EJ Manuel, posting a 1-2 record. He has thrown for 652 yards, three touchdowns and two interceptions.
If Lewis is unable to play, the Bills (3-5) will start either undrafted rookie Jeff Tuel or the recently signed Matt Flynn. Bills coach Doug Marrone said he would wait to decide who will start in that scenario but said Tuel received more reps at practice Friday.
''That's really not finalized, in our minds,'' Marrone said.
Running back C.J. Spiller is listed as probable and is expected to play after missing last Sunday's game against the New Orleans Saints with a high ankle sprain. Linebacker Manny Lawson (hamstring) is also expected to return after sitting out vs. New Orleans.
Wide receiver Stevie Johnson, who battled through a hip injury against the Saints, is probable.