Harrison is experiencing tightness in his left hamstring, and it's unclear as to when he could begin a rehab assignment, Chris McCosky of The Detroit News reports.

EDGE Analysis

Harrison was reportedly closing in on a rehab stint, but following this latest setback, the Tigers are unsure when the 32-year-old could see minor-league action. Skipper Ron Gardenhire mentioned that Harrison's hamstring discomfort could be due to the breaking up of scar tissue. Harrison will likely head for further evaluation to uncover the root of the issue.