Jason Giambi will be sidelined for three-to-four weeks with a broken rib in his right side.

Giambi was hit by a pitch thrown by Edwin Jackson of the Chicago Cubs in the third inning on March 7.

X-rays at the time were negative, but the 43-year-old had felt increased discomfort over previous five days.

"As he continued to show tenderness, we got him an MRI yesterday," Terry Francona said. "We treat the symptoms. He will be down for a number of days without activity, just getting treatment. Then when the symptoms are better, we can start getting him into activities. Then we can get him into baseball activities."