South Carolina won’t have its primary catcher, freshman Grayson Greiner, for this weekend’s NCAA tournament regional in Columbia.

Greiner suffered a torn lateral meniscus in his left knee in Wednesday’s practice. He will undergo arthroscopic surgery today and will miss at least the regional, according to USC. His prognosis beyond that is unclear.

Greiner has started at catcher in 42 of USC’s 57 games this season. Junior Dante Rosenberg started the other 15 games. Rosenberg played just two games in 2011 because of a back injury that resulted in him redshirting.

Rosenberg has played in 24 games and has a .255 batting average with seven RBIs.

Greiner’s .236 batting average ranks seventh among USC’s eight regular position players, but he is third on the team with six home runs and 31 RBIs.

His slugging percentage, .420, also ranks third.

USC will likely miss Greiner most on defense. He has thrown out 17 of the 39 runners who tried to steal against him and he has just one error. Rosenberg has two.