"He took all the snaps and feels good," Reid added. "We just have to follow this protocol as closely as we possibly can."
The team officially listed Mahomes (concussion and toe injury) as limited Wednesday.
Mahomes was injured in the third quarter of Kansas City's 22-17 win over the Cleveland Browns in the AFC Divisional Round on Sunday. He was placed in the NFL's concussion protocol and must pass all tests before being cleared to play against the Bills.
NFL Network's Ian Rapoport reported prior to Wednesday's practice that Mahomes wasn't experiencing any symptoms and was scheduled to undergo tolerance tests.
Per the NFL's concussion protocol (h/t The Athletic's Lindsay Jones), players must progress through five phases ranging from rest and an evaluation of symptoms to neurological tests that determine if brain function has returned to baseline levels.
"Only if symptoms remain at bay during all of these phases will Mahomes be cleared to return, either for full participation in practice or for a game," Jones wrote.
Chad Henne will be in line to start the AFC Championship Game if Mahomes is unable to play. The 35-year-old went 6-of-8 for 66 yards and one interception against the Browns. He had a crucial 13-yard run on 3rd-and-14 that was followed by a five-yard completion to Tyreek Hill on fourth down that allowed Kansas City to run out the clock for the win.
Mahomes was 21-of-30 for 255 yards and two total touchdowns against Cleveland prior to his injury.