Zack Greinke was back in the Dodgers' clubhouse Wednesday, his left arm in a sling three days after he underwent surgery on his left collarbone.

Greinke was injured when Carlos Quentin charged the mound after being hit by a pitch.

Greinke said he regrets not telling his catcher, A.J. Ellis, about a history of bad blood with Quentin before last Thursday's game at San Diego.