Hannahan was diagnosed with inflammation inside a capsule of his shoulder. It bothered him to hit and after throwing.
"I would throw and [the shoulder] just wouldn't bounce back," he said. "As far as the timetable, I have no clue. Once these guys get back [from next week's road trip], I should start up a throwing program and get back out there as soon as I can."
Mark Sheldon is a reporter for MLB.com. Read his blog, Mark My Word, and follow him on Twitter @m_sheldon. Manny Randhawa is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.