Graterol was diagnosed with right side soreness after exiting Thursday's game against the Cubs, Juan Toribio of MLB.com reports.
Graterol exited his appearance after just four pitches and was seen pointing to his side while being examined by trainers. According to Jack Harris of the Los Angeles Times, the right-hander experienced cramping around his ribs, and he'll undergo some testing to help determine whether a trip to the injured list is necessary. Any absence would put an extensive amount of stress on a Dodgers bullpen that is already missing several high-leverage arms.