Duffey is expected to be recalled from Triple-A Rochester on Friday, Mike Berardino of the St. Paul Pioneer Press reports.
After Fernando Rodney was dealt to the Athletics on Thursday, the Twins are in need of a reliever, so they'll add Duffey to the 25-man roster. He's made seven appearances out of the bullpen for Minnesota in 2018, although he's accrued an ugly 6.35 ERA with eight strikeouts across 11.1 frames.