The injury occurred while Workman was pitching for the Red Sox in his last outing during Spring Training, which is why the club reversed the option.
"He attempted to throw a bullpen [session] after he was optioned and there was discomfort there," said Red Sox manager John Farrell. "I think anytime someone gets a second opinion with Dr. Andrews there's concern. To what extent there is damage or injury remains to be seen, and what the follow up treatment will be as a result remains to be seen also."
Workman emerged into a key bullpen piece for the Red Sox down the stretch of the 2013 championship season. Last year, he was inconsistent as a starter.
The plan for Workman this year was to work exclusively out of the bullpen.
Ian Browne is a reporter for MLB.com. Read his blog, Brownie Points, and follow him on Twitter @IanMBrowne. This story was not subject to the approval of Major League Baseball or its clubs.