BOSTON — Would-be Red Sox closer Andrew Bailey said he is “fairly confident” he will be back by the end of the season after surgery to repair a ligament in his right thumb.

Bailey had surgery Wednesday to repair a torn ulnar collateral ligament and said he expects to return and help out the beleaguered bullpen before the season is out.

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Andrew Bailey The Associated Press

“The whole season isn’t lost. There’s a lot of good in that,” Bailey said Friday during a conference call. “It’s still very frustrating to have to start the year like this.”

Bailey was injured while covering first base in a March 21 spring training game against Pittsburgh. He tried to pitch through it, but “it got worse and worse,” he said.

Bailey will spend the next 10-14 days in a soft cast before he can begin rehabbing. Meanwhile, the Red Sox are looking for a closer to replace Bailey. He was acquired to replace Jonathan Papelbon, who saved 219 games and posted a 2.33 ERA during seven years in Boston.

Papelbon, who got the last out of the 2007 World Series sweep of Colorado, left as a free agent in the offseason, taking a $50 million, four-year deal from Philadelphia.

The Red Sox acquired Bailey in a trade with Oakland. But his injury troubles, which put him on the disabled list in each of the previous two seasons, quickly resurfaced. He strained a lat muscle in his entrance physical and missed the early part of spring training before returning to pitch in six games.

The latest injury was bad luck.

“It’s just a freak thing,” he said. “It’s not really a throwing injury. It’s trying to be an athlete and cover first base.”

With Bailey out at least until the All-Star break, the Red Sox are hoping to find a closer from within. Alfredo Aceves and Mark Melancon are possibilities, but they’ve already failed once.

The Red Sox rallied from a 2-0 deficit in the ninth to tie the opener against Detroit on Thursday, but the Tigers got back-to-back, one-out singles against Melancon in the bottom of the ninth. Aceves hit Ramon Santiago on the foot to load the bases before Austin Jackson singled past a drawn-in infield.

Bailey said the Boston bullpen is strong without him.

“There’s a lot of good arms down there. Those guys are going to have a good year. I’m hoping to join them soon,” he said. “It’ll figure itself out. The bullpen is going to be fine; I know that. They’ll be able to hold it down until I’m able to get back and help them out.”