Trivino has been managing back spasms over the past few days and was unavailable for Wednesday's loss at Detroit, Matt Kawahara of the San Francisco Chronicle reports.
Trivino hasn't pitched in a game since last Thursday, and he has an 0-3 record with two blown saves while giving up six runs in his past three appearances. It's unclear how the injury will affect the right-hander's availability for Thursday's matchup with the Tigers and the weekend series against the Blue Jays.