SAN FRANCISCO -- Giants right-hander Matt Cain has been placed on the 15-day disabled list with a lower back strain.
Thursday's move comes a day after Cain allowed six runs over 4 innings in a 6-5 loss to Pittsburgh.
Cain has struggled most of the season at the back end of San Francisco's rotation. He is 4-8 with a 5.81 ERA in 17 starts.
A three-time All-Star, Cain has already missed 43 games this season during two previous stints on the disabled list because of a strained right hamstring.
Manager Bruce Bochy said the Giants will skip Cain's spot in the rotation rather than make a roster move or use someone out of the bullpen.
Reliever Cory Gearrin was activated from the disabled list to take Cain's spot on the roster. The right-hander has a 3.89 ERA in 41 games for the Giants this year.