DENVER -- Outfielder Aaron Altherr has been placed on the 10-day disabled list with a strained right hamstring, the Phillies announced Saturday.
Altherr injured his hamstring during Friday's 4-3 loss to the Rockies and notified manager Pete Mackanin after his seventh-inning RBI single. Outfielder Cameron Perkins, optioned to Triple-A Lehigh Valley on Tuesday, was recalled to the Majors.
Before Saturday's game at Coors Field, Mackanin said there is no timetable for Altherr's return yet, and the Phillies will use a rotating outfield cast in Altherr's absence.
"I'm just gonna wing it," Mackanin said. "There's nothing to be happy about not having [Altherr] available. You get upset about it because you wanna see that guy out there in the lineup."
Daniel Nava got the start in right field Saturday for the Phillies.
Nick Williams could also see some time in right field, but Mackanin likes him better in left field, as Citizens Bank Park's right-field fence can be tough to read. Hyun Soo Kim would play only left field if needed in the outfield, because that's his most comfortable spot, Mackanin said.

Altherr had been the Phillies' best hitter this season, Mackanin said, and his nagging hamstring injury could be a result of playing more than expected. Altherr also missed 10 games in July with the same injury.
"I don't know if that has an effect on his abilities or not; it's something to think about," Mackanin said. "But as far as his performance on the field, it's nothing but positive feedback from me. I think he's done very well, to where he might be an everyday outfielder for us."
On the season, Altherr is hitting .285/.357/.536 with 16 home runs in 87 games. Perkins is 12-for-58 (.207) with four doubles in the Majors this season.