Swarzak is on the disabled list retroactive to July 25 with a mild right rotator cuff strain. He last pitched on July 24, when he gave up two runs in one inning against the White Sox in Chicago.
"He felt great," Twins assistant general manager Rob Antony said of Swarzak's eight-minute bullpen session. "I think the plan is to activate him and bring him on the trip with us to Seattle."
Swarzak, 26, has a 4.43 ERA in 31 appearances, including four starts this season. He has fared better in long relief with a 3.02 ERA in 50 2/3 innings, compared to an 8.35 ERA in 18 1/3 innings as a starter.