Graterol wasn't available for Thursday's game against Arizona due to back tightness, Juan Toribio of MLB.com reports.
Dodgers manager Dave Roberts revealed after the team's 5-2 win that he didn't use Graterol in the contest because the reliever's back tightened up in the middle of the game. Evan Phillips ended up nabbing his second save of the campaign, and he may be emerging as the team's first choice in closing situations. It's unclear if Graterol's back issue will cause him to miss additional time.