Because he believed in Wily Mo Peña's potential, Red Sox general manager Theo Epstein set aside his friendship with pitcher Bronson Arroyo and certain hostile fan reaction to trade Arroyo for the unfinished slugger 17 months ago.
Friday, Epstein traded Peña to the Washington Nationals for a player to be named, and acknowledged that the acquisition of Peña had fallen short of projections.
"It didn't turn out the way we wanted it to," Epstein said between games of the doubleheader against the Angels. "In terms of a pure talent standpoint, it's still subject to debate. There's a chance he could still blossom as a hitter. But here the fit never materialized . . . That's one we'd probably like back. Trades, they don't all work out."
The trade was announced minutes before Game 1. The Sox moved Peña to create a roster spot for pitcher Clay Buchholz, who won his big league debut, then was optioned back to Pawtucket to make room for Jacoby Ellsbury, who led off and played center field Friday night.
Ellsbury was expected to return to Pawtucket after Friday night's game, with Bobby Kielty, the former Oakland outfielder signed to a minor league deal Aug. 6, getting promoted in time for Saturday's game. The switch-hitting Kielty is expected to stick as Peña's replacement, primarily because he gives manager Terry Francona a righthanded-hitting option off the bench.
Epstein said he was not in a position to reveal the identity of the player acquired from the Nationals. "We're actually pretty pleased with the way things turned out," he said. "We're getting a player we really like.
"We're fairly happy with the resolution, given the circumstances. As far as the bigger picture, I think the fact that we traded Wily Mo doesn't mean we don't necessarily believe in his talent, but we were kind of running out of time for the fit to happen.
"It's tough for a 25-year-old kid not to get everyday at-bats. This is probably best for him, giving him a place he can play every day, and we get a player back we like quite a bit.
"The bench we have going forward in August and September is more functional for this particular club. It's unfortunate. I don't think we were selling high. You never like to sell low on a guy."
According to one source with direct knowledge of the deal, the player the Sox will receive is in another organization: Chris Carter, a lefthanded-hitting first baseman and former Stanford star who is batting .328 with 18 home runs and 81 RBIs for Tucson, Arizona's Triple A affiliate. For Carter to come to the Red Sox from Washington, of course, the Nationals would first have to trade for him. Washington GM Jim Bowden would not comment last night through a Nationals spokesman.
Peña batted just .218 with five home runs and 17 RBIs in 73 games for the Sox, 40 of them starts. That was a major dropoff from the .301, 11, 42 he posted last season in 84 games. His performance especially suffered at Fenway Park, where he hit a ghastly .134 (11 for 82) with one home run and four RBIs; last season in the Fens, he hit .322 (48 for 149) with five home runs and 24 RBIs.
In going to Washington, Peña will be reunited with Bowden, who traded for him once before when he was with Cincinnati and Peña was in the Yankees' system.
"He's the type of player who needs to play every single day," Bowden said. "When you need to work on your defense and you're striking out once every three times, you're not the kind of player who can come off the bench and help a team."
Bowden said the plan at first is to have Peña platoon with Ryan Church in left field.
"We told him that he's out of shape," Bowden said. "We need to get him in shape and baseball-ready. But we also know his power."
Amalie Benjamin of the Globe staff contributed to this report.