Duffy was removed from Wednesday's game with Triple-A Durham after aggravating his left hamstring injury, Neil Solondz of the Rays Radio Network reports.
Duffy was playing the outfield during his rehab assignment with the Bulls, but apparently aggravated the issue running out a groundball, per Durham broadcaster Patrick Kinas. The 28-year-old had his rehab stint "paused" for a few days a couple weeks ago, but Wednesday's aggravation has potential to be an actual setback. Duffy has been battling the hamstring issue since late February.