KANSAS CITY, Mo. -- Chiefs rookie safety Juan Thornhill tore his left ACL in Sunday's 31-21 win over the Los Angeles Chargers, dealing a disappointing blow to a Kansas City defense heading into the postseason.
Chiefs head coach Andy Reid confirmed the diagnosis on Monday.
“He's had a heck of a year,” Reid. “He's a good football player, has a great future ahead of him. This will slow him down a little bit, but he'll be back and ready to go.”
The Chiefs selected Thornhill in the second round of this year's draft, the No. 63 overall selection. He started all 16 games for the team this season, collecting 57 total tackles. His three interceptions rank second on the team behind Tyrann Matheiu with four. Pro Football Focus credited Thornhill with yielding a passer rating of just 69.9 on throws in his direction, with a 56 percent completion rate.
Thornhill sustained the injury on a safety blitz during the second quarter against the Chargers. His left leg appeared to slip as he changed direction. He limped off the field with assistance from trainers, and appeared in the locker room after the game with a brace on his left knee.
The loss of Thornhill will requiring tinkering with the the Kansas City secondary for defensive coordinator Steve Spganuolo. The rookie's emergence on the back end had allowed Mathieu to spend more time playing close to the line of scrimmage. In Thornhill's absence Sunday, Mathieu spent more time on the back end than usual.
Cornerback Kendall Fuller played a season-high 12 snaps as a free safety on Sunday and second-year safety Armani Watts also played a season-high 38 snaps. Reid said both played well filling in for Thornhill.
“Both those two I thought did a nice job of stepping in and playing,” Reid said. “Kendall's kind of played everywhere, great flexibility there. Spags will work it out and fill in that spot. All players are different, so you play with their strengths. That's what Spags is very good at doing.”