Updated

Running back Anthony Brown has quit Southern California's football team, and coach Steve Sarkisian was stunned by Brown's apparent accusations of racism against him on social media.

"Couldn't play for a racist man!" was posted Thursday on what USC said was Brown's Instagram account, which was later deleted.

Sarkisian calls the apparent accusation "ridiculous." Several players immediately jumped on social media to defend the first-year USC coach.

Brown is a senior who has started six games at cornerback for the Trojans. He played in only two games last year due to ankle injuries.

Brown moved to running back this season. He is listed fifth on USC's depth chart at tailback.

Brown's acrimonious departure is another blow to a program already reeling from the bizarre saga of cornerback Josh Shaw.