The Twins needed a starter with right-hander Samuel Deduno out with left eye irritation, and decided to go with Swarzak over left-hander Brian Duensing.
"Swarzak is starting," Twins manager Ron Gardenhire said. "We didn't have to use him yesterday, so he's the most rested. So we'll run him out there and however innings it takes, and then we'll ad-lib from there."
Swarzak, 27, last pitched on Wednesday against the Yankees, when he gave up two runs on three hits over 3 1/3 innings.
He has a 4.91 ERA on the season, with an 8.35 ERA in 18 1/3 innings as a starter and a 4.05 ERA in 73 1/3 innings as a reliever. Gardenhire, though, said the club still could look to Swarzak to be part of the rotation next year.
"It depends on who we have going into Spring Training," Gardenhire said. "Everything will be worked out once we get there. He's done well in the long role."