WASHINGTON -- For most of September, Sean Doolittle noticed only glimpses of his old swing-and-miss stuff -- a well-placed fastball here, a particularly tight slider there. Yet nothing was consistent. Rarely did Doolittle look like a two-time All-Star with a career sub-3.00 ERA. Rarely did he feel like himself.

It was not until Sept. 25 against the Phillies that something clicked. Doolittle faced four batters that day, throwing 13 of his 17 pitches for strikes. He allowed a hit but generated eight swinging strikes and struck out three -- the latter feat something he hadn’t accomplished since July.

“That,” Doolittle said, “was like the first time that I really felt that I was back.”

Even at that point, not everything was rosy for Washington’s former full-time closer, who allowed a home run three days later and entered the postseason at something less than his confident best.

All he’s done since is strike out five batters in five October appearances, close out Game 5 of the National League Division Series and record a four-out save in Game 1 of the NL Championship Series. He has been a stabilizing force for the Nationals’ bullpen since his return, allowing them essentially to rely on no full-time relievers other than him and Daniel Hudson.

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“We knew Doo was going to get back to what he was doing before,” Hudson said. “You knew he was going to come back, and come back strong. He’s a pro, man. He’s done it for so long. He’s pitched in the ninth inning for a long time. He knows how to get it done.”

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Coming off a 2018 season that saw him produce a 1.60 ERA with 60 strikeouts in 45 innings, Doolittle began this year with 8 2/3 scoreless innings. He held a 0.95 ERA as late as May 15, but at that point, his heavy early workload -- Doolittle pitched in 15 of the Nationals’ first 32 games and recorded more than three outs in four of them -- appeared to catch up with him. While Doolittle was still producing adequate numbers in July, he admitted publicly at one point that he was “really tired.” By mid-August, Doolittle was on the injured list due to right knee tendinitis, though a more accurate diagnosis might have been left arm fatigue.

“He got killed early, man,” Hudson said. “He was so gassed. You could just kind of see it in his body. When he came off the IL, he kind of had a different life to him.”

In Doolittle’s estimation, his mojo did not entirely reappear until three weeks later, in late September. He realizes now that the time off may have been a blessing, allowing him to stay strong into the seventh month of a season. The evidence is plain to see. At a time of year when fatigue can prove crippling, Doolittle is throwing his fastball harder, with a higher spin rate, than in any other month.

That’s boosted a bullpen that ranked last in the Majors in ERA during the regular season. For all intents and purposes, Doolittle and Hudson -- manager Dave Martinez’s “dual closers” -- are that bullpen now. Doolittle and Hudson have combined for 30 outs in the Nationals' six postseason victories. All other members of their regular-season relief corps have contributed two.

In that fashion, the Nationals are distilling their foremost weakness into a strength. One half of the equation is how well Washington’s starters have performed. The other half is Hudson and Doolittle -- the latter, in Martinez’s estimation, “throwing the ball about as well as I’ve seen him pretty much all year.”

“I’ve been fortunate throughout the playoffs,” added Doolittle. “I feel like I’ve regained some of that form.”