WASHINGTON -- Patrick Corbin allowed six or more runs for the eighth time this season, leaving the Nationals no choice but to play from behind from the start. The southpaw hurled just four innings before his night was over.

In the 6-0 loss to the Rockies on Saturday at Nationals Park, manager Dave Martinez needed to get creative to cover the remaining 15 outs.

After tossing a scoreless fifth inning, Ryne Harper batted for himself -- his second plate appearance of the season. The reliever struck out on three pitches but put up another zero in the sixth inning.

The Nats needed another arm that was stretched out to deliver outs. Martinez called Sean Nolin from the bullpen to make his first relief appearance in the Majors this season. The lefty held the Rockies scoreless for the final three innings.

“He threw really well,” said Martinez regarding Nolin’s first appearance out of the bullpen since Sept. 22, 2014. “He mixed all his pitches. The big thing is that he threw strikes when he needed to. Both him and Harper did really well.”

All told, the bullpen allowed just two hits, giving Washington ample opportunity to attempt a rally and even the score. But despite tallying eight hits, the Nationals stranded four runners in scoring position and were shut out for the 10th time this season.

Pitching out of the bullpen has been a struggle for Washington's arms this season. The bullpen owns the fifth-highest ERA (4.97) in the Majors entering Saturday. However, the club isn't focused on lowering that ERA, but rather on getting its pitchers back to their typical selves. Whether that means sending them to Triple-A -- as was the case for Tanner Rainey, who was send down on Aug. 1 to work on throwing strikes and getting his mechanics back -- or moving a starter into the bullpen to keep them stretched out.

Martinez envisions Rainey, who was called up prior to Saturday’s start, to pitch at the back end of the bullpen. After spending nearly a month with Triple-A Rochester, the righty reliever had started to perform at the level Martinez knew was possible.

Now, with Rainey back in the Majors, the skipper has another reliever to cover those big frames in the late innings, in turn taking some pressure off of Kyle Finnegan, who is showing signs of fatigue as the Nationals' go-to late-inning arm.

In his first full season, Finnegan has been lights-out for the Nats. Prior to his previous two uncharacteristic outings, Finnegan was the only reliever on the active roster who owned an ERA of 3.00 or lower, plus he had recorded a team-high nine saves and 12 holds. The righty has pitched when it matters most, closing out 22 games for the club.

“He’s the first one that tells me, ‘Hey, I'm good, I want to finish the season out strong,’” Martinez said. “I believe him when he tells me that. This guy's a workhorse, man, and he wants to do everything he can to help us win. I mean, he's more frustrated than anybody.”

With just a couple weeks left in the season, players are apt to be fatigued, especially younger players who haven’t played in a full 162-game season. That is part of what is going on with the Nationals' bullpen.

“There's a lot of other guys right now in [Finnegan's] position, and they are going to [the postseason],” Martinez said. “They're going to pitch a lot more. So for me, it's more of a mental thing. I want them to understand that, ‘Hey, you know, put yourself in a spot where you’re pitching for more than just a couple more weeks.’ We're actually looking for guys that can go do that. … Over the next two weeks, I'm looking for guys that can mentally get through this grind.”