Kansas City Chiefs quarterback Patrick Mahomes remains in the NFL's concussion protocol, and it's too early to say that he definitely will play in Sunday's AFC Championship Game against the Buffalo Bills, sources told ESPN's Adam Schefter.

Mahomes cleared certain steps Monday, "some big steps," sources told Schefter, but the reigning Super Bowl MVP still must go through other steps to clear the concussion protocol in the coming days. There is hope and optimism, considering he is expected to practice Wednesday, a source told Schefter.

Players are allowed to practice in a limited fashion while still in the protocol, which includes five steps players need to clear before being removed.

Additionally, Mahomes is dealing with a toe issue. However, coach Andy Reid said Monday that he doesn't think that injury will be a problem.

"Yeah, I think he'll be OK there for right now with the toe part," Reid told reporters Monday. "I think we'll be all right there."

Reid said Monday that the Chiefs would have a plan whether Mahomes or backup Chad Henne starts at quarterback.

Bills coach Sean McDermott acknowledged Monday that his team will have to "prepare for both quarterbacks."

"We've got work to do to prepare," McDermott said. "Certainly have a lot of respect for Patrick and how he plays the game and what he adds to their offense. But as you saw with the weapons that they have and the system that Andy runs -- I thought Henne came in and did a really good job and won the game for them there. So we've got a lot of work to do as a team, and also in this case on our defense, to get ready."