The Chiefs (14-2) got a massive blow to their title defense when Patrick Mahomes left Sunday’s game after a third-quarter hit. He was ruled out of the game with a concussion.
The Browns (11-5) have thrived in their underdog role in the playoffs, as evidenced by the glee with which they dispatched the Steelers in the wild-card round. With a victory against the Chiefs, the Browns would reach the A.F.C. championship game for the first time since the 1989 season. The Chiefs, conversely, could become the first A.F.C. team to host three straight championship games. The only other team to accomplish that feat, the Philadelphia Eagles from 2002 to 2004, was also coached by Andy Reid.