The Phillies said Pettibone will stop throwing for five days before attempting to throw again Saturday. No MRI has been scheduled.
"We'll see how he bounces back," Phillies general manager Ruben Amaro Jr. said.
Pettibone finished last season on the disabled list because of shoulder inflammation, so this is worth following. It could become an issue because Cole Hamels said he expects to miss the beginning of the season following discomfort in his left shoulder. Hamels' absence would leave Cliff Lee, A.J. Burnett, Kyle Kendrick and Roberto Hernandez in the top four spots of the rotation. The fifth spot would be a competition among Miguel Alfredo Gonzalez, Ethan Martin, Sean O'Sullivan, Jeff Manship and others, if Pettibone cannot compete.
"I look at this as a setback, so odds are he can be a little bit behind," Phillies manager Ryne Sandberg said.
Sandberg also mentioned right-hander B.J. Rosenberg could be stretched out to start, if needed. He has started in the past.
Todd Zolecki is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.