Red Sox reliever Bobby Jenks has been hospitalized and was to undergo a colonoscopy after falling ill, Terry Francona told reporters in Minnesota on Monday.
Jenks had been scheduled to throw a bullpen session Sunday at Fenway Park, but he was never seen.
Francona said his right-hander, who is on the disabled list with a back strain, became "real sick," the latest in a long line of Red Sox players to have stomach and intestinal issues this year.
If the bullpen session went well, Jenks was to head to Fort Myers to pitch in some simulated games before beginning a rehab stint at Triple-A Pawtucket. That will have to wait.
Jenks has been on the DL three times this season. He is 2-0 with a 6.32 ERA in 19 games.
