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MIAMI (AP) — While the offense for the Washington Nationals is finally healthy, their bullpen just became much stronger – but perhaps unhappier.

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Armed with new closer Jonathan Papelbon for the stretch run, the NL East leaders continue their series with the Miami Marlins on Wednesday night.

Holding a tenuous one-game lead atop the division, Washington (52-46) bolstered its relief corps by acquiring the six-time All-Star with 342 saves on Tuesday from Philadelphia. Papelbon, who would not agree to the trade unless he was guaranteed the closer’s spot, also restructured his contract for 2016.

“All-Star closer, been in pressure situations his whole career, so we’re happy to have him,” Nationals manager Matt Williams said.

Papelbon has been well-rested due to the Phillies’ struggles. He’s converted all 17 of his save opportunities and appeared in only 37 games – a number he reached July 9 last year. While Drew Storen will be demoted to set-up man, general manager Mike Rizzo envisions a potent back-end combination to complement a rotation that has been overpowering at times.

“Papelbon is our ninth-inning pitcher,” Rizzo said. “Drew will pitch the ninth inning at times when Papelbon is unavailable and be our set-up guy in the eighth inning as we are constructed today. Paps hasn’t pitched too many three-days-in-a-row stints. We’re going to be careful with him and we feel that we’ve got two terrific, elite ninth-inning guys who can close out games in pressure situations.”

Storen, who converted his last seven save chances and 29 of 31 for the season, did not take the news well.

“All I’m going to say is that I’m aware of the move and I’ve talked to Mike about it and talked to my agent and we’ve had some ongoing discussions and until those have progressed I’m going to leave it at that and no comment for now,” Storen said after losing the closer’s role for the third time with the Nationals.

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Doug Fister (3-6, 4.50 ERA) hopes to get more help from an offense which now has Anthony Rendon, Ryan Zimmerman and Jayson Werth all back from injuries. Tuesday’s 4-1 loss was the first time this season they were in the lineup together as Zimmerman and Werth both came off the disabled list, four days after Rendon was activated, and the trio went a combined 4 for 10.

Fister is 0-3 with a 5.32 ERA in his last four starts but has been given just four runs of support. He hasn’t received more than one run in any of his six outings outside Nationals Park, losing the last three.

The right-hander was reached for four runs and nine hits over five innings for the second straight start Thursday, losing 7-3 at Pittsburgh.

However, Fister has been dominant in three starts against the Marlins, going 2-0 with a 1.14 ERA.

Tom Koehler (8-6, 3.16) has a 1.62 ERA in his past six starts and is coming off one of his best to beat San Diego. He allowed three hits and four walks with seven strikeouts in seven innings of a 4-0 victory Thursday.

It’s been a very simple formula this year for the right-hander – when the Marlins (42-58) give him three or more runs, he’s 6-0 with a 2.61 ERA in eight outings.

“I know the guy continues to step up and battle,” manager Dan Jennings said. “He’s truly one of those guys that leaves everything on the field.”

Koehler defeated Washington on April 25, going 7 1-3 innings of an 8-0 win, but was roughed up for five runs in seven innings in his most recent outing against the Nationals, a 7-5 defeat May 6.

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Bryce Harper homered three times off Koehler that day but enters this matchup having gone a season-high nine straight games without an RBI.