DETROIT - The Red Sox bullpen was weakened when record-setting closer Jonathan Papelbon fled to Philadelphia as a free agent. Then reliable setup man Daniel Bard was moved into the rotation.
When new closer Andrew Bailey was lost to a thumb injury on the eve of the season, transition turned into turmoil as those relievers further down the line were pressed into more vital roles.
The ripple effect swamped the Red Sox on Opening Day as the bullpen allowed two runs in the final two innings in a 3-2 loss against the Detroit Tigers.
The crowd of 45,027 at Comerica Park on Thursday celebrated a walkoff victory when Austin Jackson grounded a single down the third base line in the ninth to drive in the winning run.
After Jon Lester allowed one run over seven innings, four Red Sox relievers faced 10 Tigers batters. Six reached base.
In Pittsburgh, Papelbon threw a perfect inning for his first save with the Phillies. Bard watched the game from the dugout, waiting for his start on Tuesday in Toronto.
New Red Sox manager Bobby Valentine was left having to defend how he used the bullpen.
“We had an elusive couple of outs there,’’ he said.
The Sox, stifled for eight innings by reigning MVP and Cy Young winner Justin Verlander, scored two runs in the top of the ninth to tie the game off Tigers closer Jose Valverde.
Dustin Pedroia led off with a double to the gap in right. Adrian Gonzalez followed with a single and David Ortiz with a sacrifice fly.
Kevin Youkilis struck out. But Ryan Sweeney, 2 for 4 in his Sox debut, drove a triple to right field to tie it. Cody Ross had a chance to give the Sox the lead but lined to shortstop.
Sweeney hoped for a second that his ball might clear the fence.
“He threw me a split-finger down and in and I thought I got it at first when I hit it, but it just hit off the wall,’’ he said.
Valentine called on Mark Melancon to start the ninth inning. He got an out before giving up singles by Jhonny Peralta and Alex Avila.
“With the righthanders coming up, I didn’t think there was any reason Mark couldn’t start that inning,’’ Valentine said.
With runners at first and second, Valentine called in newly minted closer Alfredo Aceves. Melancon, who had 20 saves for Houston last season, was surprised.
“Yeah, it felt a little quick,’’ he said. “But that’s not my job. My job is to get outs.’’
Said Valentine: “It’s a tie game on the road, so Melancon is going to try and get us the inning out, and as soon as it got to be a jeopardy situation I wanted to try and close the door with the last guy who’s going to really be the closer.’’
Aceves, who worked as a starter throughout spring training, pushed Ramon Santiago off the plate with a 0-1 fastball. That had him set up for a curveball.
But catcher Jarrod Saltalamacchia missed the ball as it drifted inside and it struck Santiago on his back foot to load the bases.
“I missed my spot,’’ Aceves said.
Valentine thought Santiago had swung at the ball - a notion backed by replays - and briefly asked plate umpire Dale Scott to clarify what had happened.
“Ace threw a pretty good pitch that got by the catcher and hit the guy in the foot, I guess,’’ Valentine said. “He didn’t swing at that ball, huh?’’
Jackson then hit a hard grounder down the third base line, well out of the reach of Nick Punto, to win the game.
“A great feeling,’’ said Jackson of what he said was the first walkoff hit of his career.
Conventional baseball wisdom says not to use your closer in a tie game on the road. But Valentine defended the move, pointing out that Aceves’s versatility would have made him available for the 10th inning had he escaped the jam.
Aceves had no problem with it.
“No. The manager has his own decision,’’ he said. “We have to be out there ready for him . . . that’s the way I think.
“Always we have the communication with our bullpen coach and the coach on the bench. We were on the same page.’’
The bullpen also failed the Red Sox in the eighth inning. Veteran Vicente Padilla, a reluctant reliever, started the inning and allowed a triple by Jackson. Sweeney got turned around on the ball, which went to the wall in right.
With the infield in, Brennan Boesch grounded to short and Jackson had to hold. Miguel Cabrera was intentionally walked.
In came lefthander Franklin Morales to face Prince Fielder, who hit a shallow fly ball to center. Jacoby Ellsbury broke in and was lined up to make a good throw. But it was weak and Jackson scored without a play.
The poor bullpen work stood in sharp contrast to that of Verlander and Lester.
Verlander allowed two hits with one walk and seven strikeouts. The Red Sox advanced only two runners beyond first base against him. The crowd chanted “MVP! MVP!’’ when Verlander walked off the mound in the eighth inning.
Lester was nearly as good, giving up one run on six hits. He walked three and struck out four. Avila had an RBI double in the seventh inning after Lester seemingly had him struck out on a 2-2 cutter that caught the outside corner.
“Lester was terrific. He did just what he needed to do, go out there and put up innings. He did a great job,’’ Valentine said.
If only the bullpen had met that challenge.
“You can’t blame anybody. It hurts no matter how you lose,’’ Pedroia said. “You hate seeing the other team celebrate.’’Peter Abraham can be reached at email@example.com. Follow him on Twitter @PeteAbe.