Patrick Mahomes Tears ACL in Loss to Chargers

Patrick Mahomes' season is over after a devastating knee injury took him out of Sunday's game ... with the team just announcing he's torn his ACL.

The Kansas City Chiefs quarterback led his squad against the Los Angeles Chargers ... and, down 16-13 later in the fourth quarter, Mahomes rolled out to the right -- looking to make a play with his legs.

Watch at your own risk ... Mahomes throws the ball away to avoid a tackle for loss -- but his left knee lands awkwardly and gives out.

PM was clearly in pain on the field ... crying out in agony and taking his helmet off -- while several of his teammates kneeled on the gridiron to say a silent prayer for their captain.

A couple trainers helped Mahomes off the field for evaluation ... and, they eventually walked him to the locker room -- with the 2-time NFL MVP putting basically no weight on the leg.

To make matters worse ... Mahomes' replacement, Gardner Minshew, came in and throw a game-ending interception deep in Chargers territory. The loss ended the Chiefs playoff hopes for the season.

Chiefs fans' worst fears were realized later in the evening ... when the team announced Mahomes had torn his ACL on the play. The post on the official social media account states, "Patrick and the club are currently exploring surgical options."