The two-time MVP quarterback was sidelined the rest of the game for backup Carson Wentz after getting his ankle twisted up with 7:57 remaining in the fourth quarter.
The Chiefs went on to win the game 21-7. But, in a race for the number one seed in the AFC and obtaining home-field advantage throughout the playoffs, the Chiefs' odds will dwindle little by little if Mahomes can't return in the coming weeks.
And with three games left in the season against the Houston Texans (December 21st), Pittsburgh Steelers (December 25th), and Denver Broncos (January 5th), that will prove to be difficult.
Mahomes had a rough outing against the Browns, completing just 19 passes on 38 attempts for 159 yards and two touchdowns. According to Chiefs head coach Andy Reid, Mahomes wanted to go back in but was denied.
The Chiefs possess the league's best record at 13-1 and have already clinched their ninth straight AFC West title.