Chivas USA midfielder Thomas McNamara has a torn ACL and meniscus in his right knee, the club announced Friday.
McNamara was hurt in Chivas' 1-1 draw with Seattle last Saturday.
Chivas said the promising 23-year-old will have surgery to repair the knee but did not specify a date or a recovery timeline, though a return this season would seem unlikely given the injury.
McNamara has started all of Chivas' games this year and scored in the season opener against Chicago. Chivas selected him out in the second round of the league draft in January.