The team announced the move on Wednesday. The 28-year-old Hughes went 1-3 with a 3.83 ERA last season as a reliever for the Royals.
Adding Hughes brings a much-needed lefty into the mix for the Twins bullpen. Jose Mijares and Glen Perkins will also be considered for the relief corps, with Brian Duensing another possibility if he does not begin the season in the starting rotation.
To make room for Hughes, the Twins designated right-hander Rob Delaney for assignment. He made one appearance with the Twins last season, and spent most of the year at Triple-A Rochester.