PITTSBURGH -- Washington manager Dave Martinez has stuck with his belief that Sean Doolittle will be the Nationals’ closer as long as he is available at this point in the season. Even with Doolittle on the injured list, Martinez has doubled down on his thinking, saying the bearded left-hander has “earned it.”

But before Monday’s series opener against the Pirates, Doolittle made clear that he’s expecting more out of himself.

“That’s awesome to get that vote of confidence from your manager, right?" Doolittle said. "But I think I have to pitch better if I want to stay in that role. I appreciate him saying that, but the mentality that I’m taking back is we have some really good arms in the back end of this bullpen, and there are a few guys who could slide into that role.”

Prior to landing on the IL with right knee tendinitis on Sunday, Doolittle had been roughed up by opponents to the tune of 12 runs allowed, including seven home runs, in 10 appearances. The worst of those came his last time out, when he allowed three homers while recording just one out against the Brewers on Saturday.

“Guys have rounds of batting practice that won’t go that well,” Doolittle said. “Homer, double, homer, homer, deep fly ball -- that’s a good round of five. That’s not me. The team deserves better, and I’ve got to get myself right.”

That’s why Doolittle said he’s up for “however they want to play it” when it comes to the closer role, allowing Martinez flexibility to work matchups or slot in a hot hand like Dakota Hudson if it comes to it.

Doolittle has spent the early part of his IL stay -- which serves as a breather in addition to an injury-prevention measure -- in the weight room, doing exercises to bolster his knee, but also to help reenergize his body, which he said has been fatigued over his past few outings.

“It’s only been two days so far, but with the training staff, [we’ve been] doing a lot of things in the weight room to take advantage of the time off to re-strengthen some things that haven’t really been firing properly and get some of these movement patterns back.”

It’s not just the velocity dips that have occasionally shown up that speak to the story of his situation. Doolittle said it’s taken longer to get right warming up in the bullpen, and even when his fastball hits the 94-95 mph range he tends to work in, it lacks crucial life that helps it miss bats.

Despite the good, yet unsecure spot the Nationals find themselves in regarding this year’s National League playoff race, he’s avoiding rushing back as much as possible.

“It’s almost like that September callup: let’s get ready to go to help the team down the stretch,” Doolittle said. “…The timing of it [is] kind of a bummer, but there’s no really good time. So we think we have just enough time to get things right and be ready for the stretch run.”

Scherzer throws successful bullpen

Max Scherzer made another crucial step in proving he’s fit to return to game action Thursday at PNC Park. He threw a bullpen session Monday, reported feeling good and even told reporters, “See you Thursday.”

“That pretty much makes my job easy,” Martinez said. “... He said he felt good. I talked to him in the weight room. Everything went according to plan.”

Scherzer has pitched only one start since July 6 due to complications with his back, the most recent of which was diagnosed as a mild rhomboid strain. But he was in good spirits Monday, smiling and being “very talkative,” which was a good sign for Martinez.

However, the Nationals manager said Scherzer will be on a pitch count -- likely in the 75- to 80-pitch range -- but potentially flexible given Scherzer’s persuasive nature.

“Knowing him, he’s going to try to talk me into doing something different, but we’ve got to be smart,” Martinez said. “We’ll see how far we get with him.”

Zimmermann changes scenery in rehab

Ryan Zimmerman (plantar fasciitis in right foot) will continue his rehab stint, moving from Double-A Harrisburg to Class A Potomac.

“The big thing with Zimm is he hasn’t played much at all this year,” Martinez said. “… So we’ve got to build him up. I talked to him yesterday, he felt good, but we’ve got to try to get as many at-bats as we can.”