Minnesota also reinstated reliever Blaine Boyer from the 15-day DL prior to Wednesday night's game against Tampa Bay. Boyer had missed 15 games due to right elbow inflammation.
Graham gave up one run over two-thirds of an inning in the Twins' 11-7 victory over the Rays on Tuesday night. The Rule 5 draft pick went 1-1 with a 5.15 ERA in 34 games, including one start.
Twins manager Paul Molitor said Graham experienced shoulder stiffness during Tuesday's game.
''We're going to give Graham a couple weeks to get that thing to calm down,'' Molitor said. ''We hope it's nothing major. Our doctors will look at it when we get back to Minneapolis.''
Boyer was 2-4 with a 2.98 ERA in 51 games before going on the DL.