Giles aggravated his right hamstring while trying to beat out a double-play ball in the sixth inning of Friday's 6-2 victory over the Tigers. Giles said he initially felt the strain earlier in the week during the series at Yankee Stadium.
In Friday's game, Giles said the muscle began to spasm and he pulled up to avoid further injury.
"Hopefully, the leg will be better with Monday off. It's a few days," Giles said. "I think we caught it in time and it settled down. I don't think it is going to be a week, just a few days."
Giles is also suffering from a sore left shoulder, but manager Bud Black said he was available Saturday if necessary. Paul McAnulty started in right field.
Also out of the lineup was Kevin Kouzmanoff, who hasn't played since Sunday in Cleveland because of a sore back. The third baseman hit off a batting tee Saturday at 70 percent effort, Kouzmanoff said, and hopes to return to the lineup Tuesday.
Chase Headley started his fifth straight game -- fourth at third base -- on Saturday since his recall June 17. Headley has six hits in 16 at-bats with two homers.
Mike Scarr is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.