CHICAGO - Remember when the Twins' projected rotation was Francisco Liriano, Scott Baker, Carl Pavano, Nick Blackburn and Jason Marquis? Only Pavano remains -- and his shoulder isn't 100 percent. And we're still in May.

The ever-changing rotation will take on a different look Thursday when Eden Prairie's Cole DeVries makes his major league debut. He had his contract selected by the club Tuesday.

He'll join righthander P.J. Walters and lefthander Scott Diamond as starters who began the season at Class AAA Rochester but now are being asked to settle down a rotation that has been in flux all season and has led to the bullpen throwing the third-most innings in baseball.

"They were both pitching really well in Triple-A, they both came up here and have been pitching really well," DeVries said. "It was one of those things you look at and go, hey, if they can do it, why can't I?"

DeVries, 27, was 1-4 for the Red Wings with a 4.24 ERA. In 462/3 innings, he walked just seven batters while striking out 37. He credited Rochester pitching coach Bobby Cuellar for helping him smooth out his mechanics, leading to throwing more strikes.

DeVries, according to baseball-refence.com, will be the 33rd player from the University of Minnesota to appear in the majors. It will be a great moment for him, considering he was a non-drafted free agent when he signed with the Twins in 2006.

"I just can't say enough about how great this moment is for myself,'' he said. "All the hard work I put in. This being my sixth year of pro ball and finally getting my opportunity, it's unbelievable. It really is."

Twins manager Ron Gardenhire broke the news to Jason Marquis on Monday that he was being designated for assignment.

"It's not easy," Gardenhire said of Marquis. "He's been through an awful lot. But the bottom line is that it just wasn't getting done out on the field. Give some guys a chance and try to straighten out our rotation. We have to get deeper into games.''

Righthander Anthony Swarzak has been named the starter for Friday when the Twins open a three-game series against the Tigers. Swarzak is 0-3 with a 4.73 ERA and has thrived in a relief role, posting a 3.06 ERA as opposed to 6.75 when he starts.

But the Twins needed someone to step into the rotation following the Marquis move and the injury to Blackburn. They aren't ready to move Liriano back into the rotation yet.

Pavano will start Saturday, giving him a week between outings as he continues to work his way through shoulder issues. Pavano hasn't thrown in the bullpen between recent starts because of the shoulder, but the Twins expect him to do so this week. Pavano noticed increased velocity in his most recent outing on Saturday.

Gardenhire said Blackburn, on the 15-day disabled list because of a strained left quad, is making progress but "he still feels it a little bit."

• Ryan Doumit, who hadn't started since May 16 because of a strained right calf, returned to the lineup on Tuesday as the designated hitter.

• White Sox first baseman Paul Konerko, who was struck near the left eye with a pitch on Friday, returned to the lineup on Tuesday.

• Former Twins infielder Orlando Hudson joined the White Sox on Tuesday after being released by the Padres last week.