His head hit the turf while getting tackled by Mack Wilson in the third quarter.
Mahomes was 21-of-30 for 255 yards and a touchdown with an additional score on the ground at the time of his departure. Veteran journeyman Chad Henne, who previously started for the Miami Dolphins and Jacksonville Jaguars, entered the game for Mahomes.
Henne and the Chiefs held on to win the game and will face Josh Allen and the Buffalo Bills in the AFC Championship game. Afterward, head coach Andy Reid told reporters Mahomes is "doing great" after the injury.
The 25-year-old Texas Tech product didn't miss any contests because of injury during his first two years in the NFL. That stretch of durability ended in October 2019 when he suffered a dislocated kneecap, which forced him to miss two games.
Mahomes is one of the most valuable players in all of sports, especially given the critical nature of quarterbacks. In turn, a significant drop-off can be expected from the Chiefs offense if he is unable to play with a trip to the Super Bowl on the line next Sunday.