Red Sox center fielder Coco Crisp was a disappointment at the plate for the Rec Sox last season.

The Providence Journal / Bob Breidenbach

The Red Sox finally parted ways with outfielder Coco Crisp and in return found some help for the bullpen.

General manager Theo Epstein pulled the trigger yesterday morning on a deal that sent Crisp to the Kansas City Royals in exchange for right-handed reliever Ramon Ramirez.

“We believe we’ve acquired a young … reliever who can really help our bullpen,” said Epstein. “He’s got a plus-fastball 92-95 mph and an outstanding power changeup with a pretty good slider. He’s very quietly had a tremendous amount of success in the major leagues over the past 2½ seasons. We were looking for that type of upgrade at depth with our bullpen.”

Ramirez, 27, spent the entire season 2008 with the Royals and posted a 3-2 record with one save and a 2.64 ERA. In 71 2/3 innings of work, he recorded 70 strikeouts. He limited opponents to a .153 batting average, which was the lowest in the A.L. and third in the majors with at least 50 games in 2008. Overall, he’s held right-handed batters to a .198 average.

Originally signed by the Rangers as a non-drafted free agent in 1996, Ramirez is 9-7 with one save and a 3.62 ERA in 154 major-league games as a reliever. He has recorded 146 strikeouts in 156 2/3 innings between the Rockies and the Royals.

When the Red Sox acquired Crisp from Cleveland as part of a seven-player deal, he was coming off his most successful major-league season, in which he hit .300 with 16 homers, 69 RBI in 145 games for the Indians in 2005.

During his three-year stint with Boston, his defense was tremendous, but his offense didn’t come around the way management had hoped it would.

“He played through injuries while he was with us and he played hard,” said Epstein. “He was a big part of us winning a world championship. His efforts here are certainly appreciated and he did it with a lot of class along the way.”

Crisp said it was bittersweet being traded, but he knows he’ll have a chance to play every day. When asked how he would classify his three years in Boston, he called them a learning experience.

“I had a lot of fun and it was a great experience,” he said. “On and off the field I learned to grow, but the one negative aspect that came out of the whole thing was that I was plagued by nagging injuries the entire time I was there. It was an up-and-down ride, but most of the time I enjoyed myself.”

This trade does a few things for the Red Sox.

With Ramirez in the fold, the versatile Justin Masterson, who worked as both a starter and reliever in 2008, will probably be back in the rotation for 2009.

“Ramirez does give us the flexibility to start Masterson if that’s in the best interest of the ball club,” Epstein said. “Both Ramirez and Masterson dominate right-handed hitters, so in that way, Ramirez could potentially replace Masterson.”

Also, Jacoby Ellsbury will be the everyday center fielder.

“With the emergence of Jacoby Ellsbury we felt we would be able to find a complimentary outfielder on the market easier than we would find a valuable member of the bullpen, so that’s why we made the trade…. I think Jacoby had a very solid rookie season. I know expectations were probably unreasonably high for him. This is a more than acceptable rookie year.”

Epstein was also quick to point out Ellsbury’s work ethic, and because of that the organization knows the young outfielder will only get better with more opportunity.

Now Epstein needs to find a fourth outfielder, and he plans on acquiring a right-handed hitter who can play both center and right field and can hit left-handers. Rhode Island native Rocco Baldelli is a free agent and is a candidate for that role in Boston.

Epstein did not reply to a text message, asking him to confirm that he’s interested in Baldelli’s services, but during yesterday’s conference call he spoke generally about what he’s looking for.

“We’ll cast a wide net and look outside the organization,” he said. “There are a lot of different options and a lot of different places we can turn to fill that role.”

Epstein explained that this trade freed up $6 million for the Red Sox, so he has some room to fill that fourth outfielder’s role and address other issues, too.

jmcdonal@projo.com