The Twins optioned Rojas to Triple-A St. Paul on Wednesday.
Minnesota moved Rojas to the minors and designated right-hander Austin Voth for assignment after the two pitchers covered the first six innings of Tuesday's 12-3 loss to the Dodgers. Prior to making the two-inning start for Minnesota, Rojas hadn't pitched for the big club since late May after he had been shelved due to triceps inflammation. The Twins will likely have the young lefty get further stretched out as a member of the rotation at Triple-A.