Duffey, who had originally been scheduled to start Monday in Cleveland, will move to the bullpen, MLB.com's Rhett Bollinger reports.
Duffey will lose his rotation spot to the 22-year-old Jose Berrios, who will be recalled from Triple-A to make Monday's start. In his age-25 season, Duffey has sported his worst ERA at any level of his career (6.12) over 89.2 innings. With several other shaky back-end rotation options in Minnesota, there's a chance he could earn his job back down the road, but in the meantime Duffey's fantasy value will be highly limited.