Curtiss is expected to have his contract selected by the Twins on Wednesday, Mike Berardino of the St. Paul Pioneer Press reports.
Tim Melville was designated for assignment Tuesday to open up a 40-man roster spot that will soon be occupied by Curtiss. The 24-year-old currently owns a 1.38 ERA over 39 innings between Double-A Chattanooga and Triple-A Rochester this season. He'll likely slot into the Twins' bullpen upon his promotion.