PHILADELPHIA -- It has been a difficult task for Nationals manager Dusty Baker to navigate through the final innings of games during the past week.

Both of Washington's co-closers -- Shawn Kelley (back) and Koda Glover (hip) -- are on the disabled list. Two of the pitchers they were counting on to be their most reliable relievers -- Joe Blanton and Blake Treinen -- are sporting a 10.64 ERA and 9.22 ERA, respectively.

So Baker did not have an answer for who he would turn to protect a lead late in games this weekend in Philadelphia, something that came back to bite the Nats as they blew a lead late in Sunday's 6-5 loss in 10 innings to the Phillies. Matt Albers, who had secured his first career save Friday night, gave up a game-tying pinch-hit three-run homer to Aaron Altherr in the eighth inning. And Treinen allowed the game-winning run to score in the 10th.

"It's been difficult," Baker said. "It's been difficult since the beginning. But our bullpen -- Matt Albers that was the first mistake he made. Spring Training he had a 0.00 ERA, and it was the first mistake he's made on the slider during the season. And so that was just a mistake he didn't miss."

Treinen gave up the go-ahead run without giving up any hard contact. Odubel Herrera began the inning with a double down the line on a checked swing, which had a 9 percent hit probability according to Statcast™. Altherr was intentionally walked and Vince Velasquez reached on a bunt single before Freddy Galvis' walk-off sac fly.

"I feel like that's kind of how things have gone for me lately," Treinen said. "Guys have fought off some tough pitches and found some ways on pitches I've thought were good pitcher's pitches. The thing that hurt me tonight was not getting ahead of Altherr and putting him on. So that's frustrating."

It is the current state of the Nats bullpen, as they try and piece together the final outs lately. Jacob Turner pitched the final four innings to lock down a win Wednesday. Enny Romero secured his first career save Thursday and Albers did the same Friday. So the Nats have relied upon different relievers to step up lately, and they have been doing so with success.

Despite the uncertainty of their late innings situation, the Nationals own the best record in the Majors at 21-10.

"We've lost 10 games, it's not like we're not having success," left fielder Jayson Werth said. "It's just one game. I mean you're not going to win them all, you're not going to close them all. I think we're playing pretty good."