That tweak landed him on the 15-day disabled list.
The Phillies announced before Sunday's game against the Mets that Dobbs is out because of a strained calf. The Phillies selected the contract of infielder Miguel Cairo to take his place. To make room for Cairo on the 40-man roster, the Phillies placed left-hander Antonio Bastardo on the 60-day disabled list.
Dobbs declined to speak about the injury.
Phillies manager Charlie Manuel said Dobbs said his calf has been bothering him since last season. He also said Dobbs is expected to get his calf scanned in Philadelphia.
"We're trying to pin down exactly what's wrong with him," Manuel said.
Dobbs is expected to rehab in Clearwater, Fla., before he rejoins the team.
Cairo opened the season with the Phillies, but they designated him for assignment in May after hitting .118 (2-for-7). He accepted his assignment to Triple-A Lehigh Valley, where he hit .287 with five homers and 33 RBIs.
"I went there and played, and it was fun," Cairo said. "It kind of humbles you a little bit. If I got called up this year, it would be good. If it wouldn't happen, I've had a good career. But I'm glad to be back."
Right-hander Brett Myers was scheduled to make a rehab start Sunday evening for Class A Lakewood. Left-hander J.C. Romero and right-hander Clay Condrey are scheduled to throw bullpen sessions Monday in Clearwater.
Bastardo is scheduled to make a rehab start Monday for the rookie-level Gulf Coast League Phillies.
Todd Zolecki is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.