KANSAS CITY, Mo. -- The Chiefs' red-hot defense suffered a significant loss against the Los Angeles Chargers with rookie safety Juan Thornhill leaving the game with a left knee injury.
Thornhill will undergo MRI on Monday. The Chiefs fear the injury will keep him out of the playoffs, according to NFL Network's Ian Rapoport, but head coach Andy Reid hopes for the best.
"We'll know more tomorrow," Reid said. "He's had a great year, so we're hoping he's OK."
Thornhill was blitzing on the play and his left leg slipped without contact. He limped off the field with assistance from the trainers and headed straight to the locker room on a cart for further evaluation. Thornhill appeared in the locker room after the game with a brace on his left knee.
The injury occurred on a 12-yard touchdown pass from Philip Rivers to Keenan Allen, lifting the Chargers to a 7-3 lead with 11:44 remaining in the second quarter. That was the first touchdown surrendered by the Chiefs since the third-quarter against New England in Week 14, ending a streak of 10-straight quarters without yielding a touchdown.
Thornhill, a second-round selection in this year's draft, emerged as a reliable starter for the Chiefs in the back end of the secondary. His emergence has allowed the Chiefs defense to use Tyrann Mathieu in multiple roles, particularly close to the line of scrimmage. Thornhill has 56 total tackles on the season with three interceptions, including a 46-yard pick-six against Oakland in Week 13.
Chiefs cornerback Bashaud Breeland also left the game after making a tackle on Chargers wide receiver Mike Williams. The club labeled him questionable to return with an illness, and he latered re-entered the contest.
Tight end Blake Bell exited for a concussion evaluation. He later returned to the game.