With Jonathan Papelbon headed for the rotation after saving 35 games last year and a slim market for available closers, Boston hopes Pineiro can emerge as a consistent finisher.
"He's a guy, even when he was a starter, a lot of our reports were that he would be pretty unbelievable in the bullpen," assistant general manager Jed Hoyer said. "The early part of the season may show a lot as to who's going to be the closer later in the season, but you don't have to have your postseason roster set in April."
The 28-year-old right-hander pitched well in 2002 and 2003, but injuries set him back and he was 21-35 in his last three seasons. He had a 6.36 ERA last year and became a free agent in December when Seattle failed to offer a contract.
"After I got hurt a little bit in 2004, everything went downhill," he said. "But knowing I don't have to go out there and throw 215 innings, I think it'll be good for me."
Hoyer also expects the Red Sox to work toward finalizing their $70 million, five-year deal with outfielder J.D. Drew. The free agent outfielder reached a preliminary agreement about a month ago but his right shoulder, which underwent surgery in 2005, raised concern.
"I think the holidays interrupted some of the dialogue," Hoyer said. "I think that will pick back up here in the next little bit."
Pineiro's agreement with Boston includes $2 million in performance bonuses based on games finished and a mutual option for 2008.
Since last season, the Red Sox have added right-hander Brendan Donnelly and left-hander J.C. Romero. Potential closer candidates include Donnelly and holdovers Julian Tavarez, Craig Hansen, Manny Delcarmen and Mike Timlin.
The closer's job became vacant when the Red Sox decided to shift Papelbon into the rotation. As a rookie last year, he had an 0.92 ERA and 35 saves but didn't pitch after Sept. 1 because of a sore shoulder.
Pineiro said he received offers from other teams to start.
"I wanted to go to a team where I had a chance to win right away," he said.
He is 58-55 with a 4.48 ERA in his career. He was 8-13 in 25 starts and 15 relief appearances last season, when he made $6.8 million. He finished six of those games and had his only save Sept. 8 against Texas.
"I wasn't happy in the beginning because I wanted to keep on starting," he said of the shift to the bullpen, "but I said, 'I want to be pitching. I want the ball in my hand,' and it worked out pretty good."
Pineiro has appeared in relief 37 times. As a reliever last year, he was 1-1 with a 4.81 ERA and held opponents to a .213 batting average.
"I don't know what his repertoire will be out of the bullpen," Hoyer said, "but he has four power pitches and we thought that would translate really well."