Chase Utley (sprained right thumb) and Placido Polanco (left elbow inflammation) will each be out for at least two weeks.
Beyond that, the Phillies are unsure how long they could be without their starting second and third basemen.
"I don't have a lot of answers right now," the club's head athletic trainer, Scott Sheridan, said Tuesday.
One thing is certain: The Phillies, now with seven players on the disabled list, are in an unenviable position without Utley and Polanco, both of whom are the leading vote-getters at their positions in National League all-star balloting.
"That's a big part of our lineup," Manuel said.
Infielders Greg Dobbs and Brian Bocock were recalled from triple-A Lehigh Valley. Dobbs started at third base, and Wilson Valdez played second Tuesday against the Cincinnati Reds.
Scott Proefrock, the Phillies' assistant general manager, would not commit to making a move to acquire help from outside the organization until the Phils have a better idea of how long Utley and Polanco may be out.
"We're always looking to get better," Proefrock said. "Now our focus may be a little different than it was. But we'll explore whatever options are available."
Manuel was confident such a move could be made.
"I think in any way we can make our team stronger, or if there are things we need to get, I think we'll get them," Manuel said.
This is only the second time in Utley's career that he has been put on the disabled list. He left the ballpark hours before Tuesday's game and was not available for comment.
Utley will see hand specialist Randall Culp in Philadelphia on Wednesday. Sheridan said he and his staff had differing opinions on the severity of the sprain when they looked the results of Utley's MRI. A second opinion, they hope, will help decide what grade the sprain is.
The grade determines the amount of tearing in the ligament. Grade 3 is the worst and Grade 1 is less severe.
