ST. PETERSBURG -- Everything went well in Nick Blackburn's bullpen session Sunday morning, so the right-hander will make his third start of the season Tuesday against the Red Sox at Target Field.

Blackburn exited his April 14 start with right shoulder stiffness but reported back to the visitor's clubhouse at Tropicana Field with no soreness, saying everything felt loose and ready to go Tuesday.

"I couldn't feel anything at all, so everything seems to be pretty loosened up," Blackburn said. "It's good."

With Blackburn taking a spot in the rotation, manager Ron Gardenhire said Anthony Swarzak will join the bullpen and should be available to pitch in relief Monday. The Twins are carrying 13 pitchers on the 25-man roster but won't make a roster move until they see how Blackburn bounces back from Tuesday's outing, most likely coming on Thursday's off-day.

"Obviously no guarantees. We won't know anything until I've been out there a couple times. Just going off the bullpens I've thrown, I felt great," Blackburn said. "Every day's been such an improvement. I feel like I have to have a positive reaction from the way it's responded to all the treatments.

"Just because you don't feel something being sore or tight doesn't mean it doesn't exist. I think in the future, I'll be more on top of keeping everything stretched out. It could potentially help me throw better."

Mauer makes 16th straight start in Twins' lineup

ST. PETERSBURG -- Joe Mauer was back in the starting lineup for Sunday's series finale against the Rays. He's been there in the three-hole for all 16 of the Twins' games this season, though not necessarily in the same place defensively.

After playing only 82 games in an injury-marred 2011 season, Mauer has yet to take a day off. He has nine starts at catcher, four at first base and three at designated hitter. Rather than give him days off, manager Ron Gardenhire is looking to keep Mauer fresh by limiting the wear and tear he'd face behind the plate every day.

"That gives him a little bit of a reprieve from the daily grind and the beating up of a catcher," Gardenhire said. "That's why I don't feel like I have to do too awful much as far as breaks go, because he is DHing some, he is playing first base some, which takes a load off his body."

Part of the reason Gardenhire wanted Mauer behind the plate Sunday was so he could get lefty Francisco Liriano "on the right track" after a shaky start to the season. Gardenhire thought the two worked well together this spring, with Mauer encouraging Liriano to be more aggressive with his fastball.

"Let's not forget the most important part about Mauer catching today: We're trying to win a series," Gardenhire added. "Joe wants to be a part of that. We'd like to win two out of three and go home. Joe being in the lineup definitely gives us a better chance."

Morneau DH's Sunday to protect sore foot

ST. PETERSBURG -- Manager Ron Gardenhire mentioned the possibility Saturday that Justin Morneau would start at first base Sunday, but Morneau's sore right foot relegated him to DH duty for the second day in a row.

Morneau fouled a ball off his right foot, which required surgery last year, on Thursday night and sat out Friday before starting at designated hitter Saturday and Sunday. Gardenhire said Morneau should be able to play "some" first base when the Twins return home Monday to start a series against the Red Sox, but it simply wasn't worth risking further injury Sunday on Tropicana Field's hard turf surface.

"He said he could play -- and he'd do it -- but I don't think it's right. He's not 100 percent on his foot," Gardenhire said. "There's no sense in putting him out there."

With Morneau at DH and Joe Mauer behind the dish, Chris Parmelee started at first base for the 10th time this season.

Infielder Hughes claimed by Oakland

ST. PETERSBURG -- Former Twins infielder Luke Hughes was claimed off waivers by the A's, Minnesota announced Sunday.

Hughes was on the Twins' Opening Day roster and went 2-for-10 with two RBIs in four games before being designated for assignment Wednesday to make room for Jason Marquis. The 27-year-old infielder appeared in 96 games for Minnesota last season, batting .223 with a .289 on-base percentage, .338 slugging percentage, seven home runs and 30 RBIs.

Hughes is a career .224 hitter and has appeared in 40 games at second base, 37 at first and 16 at third. He was originally signed by the Twins as a non-drafted free agent on July 19, 2002.

Hughes entered the year off a strong Spring Training effort, posting a .303/.347/.636 batting line with four doubles and six homers in 23 games, but he was the odd man out of the Twins' infield mix once the season began.