MINNEAPOLIS — Right-hander Julian Tavarez was designated for assignment yesterday to make room for first baseman Sean Casey on the roster.

The Sox have 10 days to trade Tavarez, release him or assign him to the minors, an assignment Tavarez can veto because of his service time. Tavarez was the forgotten man in the Boston bullpen this season, appearing in only nine games, including a 1 1/3-inning stint against the Twins on Sunday night. He was 0-1 with a 6.39 earned-run average.

The move spared Craig Hansen an option to Pawtucket. The Red Sox have been impressed by Hansen’s performances in Pawtucket this season, and have seen enough good things from the right-hander in three outings with Boston over two brief periods with the big-league club to forgo the easy move — optioning him to the PawSox.

The roster move cuts the number of Red Sox pitchers to 12, adding a position player to the thin bench. Casey had been on the disabled list since April 26 because of a right hip strain. Casey was hitting .346 (18-for-52) when he suffered the injury.

Boston manager Terry Francona praised Tavarez for “saving us” last year when the team needed a starter and Tavarez gave the Red Sox three solid months in the role. But Tavarez had been reduced to a mop-up man in blowouts, and Francona thought other pitchers could help in other roles to win games, so Tavarez was designated and Hansen stays.

“The way Hansen was throwing had something to do with (the move). He’s pitching well,” said Francona. “We have a lot of confidence in Hansen. It may not have come down to one guy (or the other), maybe more of a philosophy than one guy, but we wanted to get Hansen up here last week.”

Hansen said he was sorry to see Tavarez go and that he was a bit surprised he wasn’t on his way back to Pawtucket. But he’s eager to stick around and show what he can do.

“In all honesty, I thought I was going to be sent down. I thought they’d just use my option,” said Hansen. “I was at lunch with Manny [Delcarmen] in the hotel and I saw Julian saying goodbye to everyone, so I put two and two together and figured something happened to him. That’s part of the game. I can’t control that.

“I just have to try to keep pitching well,” said Hansen. “I’ll give myself a boost of confidence if I pitch well. I feel pretty strong. All of my pitches have been working.”

Hansen pitched a perfect seventh inning last night, fanning one.

Around the bases

Shortstop Julio Lugo, who suffered a mild concussion in a baseline collision on Friday night, still isn’t ready to return to action. There have been some encouraging signs for Lugo, though. … Jacoby Ellsbury, who was hit on the inside of the left knee by a pitch in the third inning Sunday night, was held out of the starting lineup last night, though it’s just a bruise, nothing serious . . . Kevin Youkilis also got a breather, replaced by Casey at first. Casey was 13-for-25 in his career against Livan Hernandez, the Twins’ starting pitcher last night. … Dustin Pedroia nearly decapitated Hernandez with a liner in the second, but Hernandez got his glove in front of his face just in time and caught the screamer.

David Ortiz, who was caught looking for a strikeout on a 60-mph eephus changeup from Detroit’s Armando Galarraga last Wednesday, poked Hernandez’s 59-mph curveball for an RBI single through shortstop in the first last night. … Former Boston and Pawtucket pitcher Dana Kiecker, who lives in the area, was at the game with his family. … Minnesota first baseman Justin Morneau’s diving play robbed Casey of a hit in the second inning. Casey returned the favor with a diving play that robbed Morneau of a hit in the fifth.

J.D. Drew had a double and two singles in his first three trips to the plate, giving him five straight hits. He took a called third strike in the eighth, though, ending that streak, but he does have a seven-game hitting streak. … The Sox are 2-10 in domed stadiums this year, and only 8-17 at the Metrodome since the start of the 2001 season. … Alex Cora went 2-for-4 and his average dropped. Cora was batting .857 (6-for-7) heading into the game. He dipped to .727 (8-for-11).

skrasner@projo.com