"We're being very cautious with this," general manager Ruben Amaro Jr. said. `'There's no reason for him to kind of completely blow it out because it's an injury that if he hurts himself and really pulls it, we could lose him for a long time. We'll shut him down, get him right and hopefully he'll miss only a couple of starts and go from there."
Lee strained his left oblique.
"I don't know what pitch it was, but he must have made a pitch that bothered him a little bit," Amaro said.
Lee threw 10 scoreless innings Wednesday night at San Francisco but got a no-decision. The Giants won 1-0 in 11 innings.
The lefty had been scheduled to pitch Monday night at Arizona. Right-hander Kyle Kendrick is now scheduled to make that start.
To take Lee's spot on the roster, the Phillies recalled lefty Joe Savery from Triple-A Lehigh Valley.