The Kansas City Chiefs made it official on Wednesday and ended the season of running back Jamaal Charles by placing him on injured reserve.

Charles suffered a knee injury during the first quarter of last Sunday's game against Detroit. Chiefs head coach Todd Haley did not divulge the exact nature of the injury during his Monday press conference when he announced that Charles would be out for the rest of the year, but it has widely been reported to be a torn ACL.

The Chiefs filled the roster spot by promoting wide receiver Jeremy Horne from the practice squad to the active roster. Horne appeared in three games with the Chiefs during the 2010 season after joining the club as a rookie free agent.

Charles, a third-round pick in the 2008 draft, has appeared in 49 games for the Chiefs and has started 19. He has run for 3,027 yards with a 6.1 yard average and 12 touchdowns.

Named to the Pro Bowl last season after rushing for a career-best 1,467 yards with five touchdowns, the fourth-year veteran out of Texas had 12 carries for 83 yards in his brief stint this season.

The Chiefs also signed offensive lineman Lucas Patterson to the practice squad.