With all other options exhausted, Twins righthander Ricky Nolasco on Monday will undergo surgery to remove the bone fragment from his right ankle that is causing an impingement.

Dr. Robert Anderson will perform the surgery in Charlotte, N.C.

The bone fragment is causing pain when Nolasco tries to pitch. Rest, a cortisone injection and orthotics failed to alleviate the problem.

The next issue is if Nolasco (5-1 with a 5.51 ERA) will be able to pitch again this season, something General Manager Terry Ryan wasn’t sure of Monday.

“I don’t know the answer to that question yet,” Ryan said.

In 34 starts since signing a four-year, $49 million contract with the Twins, Nolasco is 11-13 with a 5.40 ERA. After going 9-15 last season, Nolasco reported to spring training looking to turn over a new leaf. But he has not performed the way the Twins expected him to.

“It’s disappointing that he’s going be out for a fairly lengthy stay,’’ Ryan said. “But we know what’s going on there, take it out, get him back and get him going.”

Sano moves around

Miguel Sano spent Monday afternoon taking grounders at first base as well as third base.

Sano was drafted as a shortstop and moved to third during his development, and now the Twins are preparing their power-hitting prospect play first base.

“We’re trying to find ways to expand defensive possibilities for him in the short term and the long term as well,” Twins manager Paul Molitor said.

Sano’s hitting is ahead of his fielding, but he continues to put effort into improving his defense. As Molitor worked with him Monday, the pair were joined by third baseman Trevor Plouffe, who also gave Sano some pointers.

“He’s got good actions over there,” Plouffe said. “I’m just trying to help him out and tell him some things that I have learned.”

Pressly to DL

Righthanded reliever Ryan Pressly stood in front of his stall, arms folded, looking rather vexed.

“This is first time on the DL in like five years, man,” Pressly said. “I don’t like it.”

Pressly landed on 15-day disabled list because of a strained latissimus dorsi muscle suffered Saturday as he threw a fastball that reached 97 miles per hour on the Kauffman Stadium radar gun. It’s not clear how long he will be out. He has called some players who have had similar problems and was told it’s based on how the body responds.

“I’m not exactly sure how long it is going to be,” Ryan said, “but it is going to be longer than 15 days.”

With Pressly landing on the DL, the Twins activated outfielder Shane Robinson from the family emergency list. Robinson left the club last week to be with his 8-month old daughter, Harper, who underwent surgery. He rejoined the club Monday.

Thompson sent down

The Twins’ bullpen shuffle continues, as they optioned lefthander Aaron Thompson to Class AAA Rochester after Monday’s game. To replace Thompson on the roster, the Twins selected the contract of lefthander Ryan O’Rourke from Rochester.

O’Rourke, 27, has a 5.40 ERA in 22 games with the Red Wings. He mainly will be used against lefthanded hitters, who he held to a .172 batting average with the Red Wings. Thompson was 1-3 with a 5.01 ERA in an American League-leading 41 games.