Thursday night, after the Washington Nationals had abandoned hope for the first time this season, Manager Davey Johnson wanted to give Jayson Werth a rest. With the Nationals trailing by six runs in the seventh inning, Werth could sit without worrying what it would cost the Nationals.

But it also meant Mark DeRosa had to jog to right field, a former everyday player and 37-year-old veteran reduced to mopping up. Afterward, Werth found DeRosa and apologized to him. DeRosa immediately told him there was no need.

“Hey, I knew what I signed up for when I signed the contract here,” DeRosa said. “That’s my job, to give him a blow. I completely understand that.”

During spring training and early in the Nationals’ season, Johnson has worked to give clear job descriptions to his cast of role players, and his methods have provided insight into how he oversees his roster. In turn, those players have embraced their positions without complaint.

Along with DeRosa, Johnson has tried to create clear identities for outfielders Chad Tracy, Xavier Nady and Roger Bernadina, utility infielder Steve Lombardozzi and Jesus Flores. Tracy, Nady and DeRosa are veterans, former everyday players. Johnson goes out of his way to not label Lombardozzi a utility infielder, even though that is exactly what he is. Flores, a former starter, once bristled at serving as a backup. He still wants to start, but he has accepted his lot and flourished on days Wilson Ramos rests.

“I always try to come out of spring with a team that knows me and knows their roles so we hit the ground running,” Johnson said. “The main thing is coming out of spring, even with the injuries we had, the cast of characters we had knew basically what their role was going to be. When you hit the ground, you’re putting your best foot forward.”

Over the past two seasons, General Manager Mike Rizzo has, with his bench, prioritized finding players with strong reputations as stabilizing clubhouse presences. Last year, he signed Matt Stairs, Alex Cora and Jerry Hairston. This year, similar roles have gone to Nady, DeRosa and Tracy.

“They’re veteran guys who knows what it takes to win,” third baseman Ryan Zimmerman said. “They don’t panic if they don’t play for a week. And if they do play, they don’t panic, either. I think those bench guys and how Davey uses them is a huge part of why we’re off to such a good start.”

Tracy has started once all season. DeRosa began the year as the primary left fielder, but he has not started in the outfield since April 17, and Johnson planned to play Nady on Tuesday.

“We get that,” DeRosa said. “It’s character. It’s wanting to win. It’s putting the team before yourself. If you look in the mirror every night and you’re honest with yourself, you know your role. I want to be here. I want to win. We got great guys in the clubhouse. We have a lot of fun being around each other. The vibe I get, there’s no selfish ballplayers in here.”

Johnson’s identifying clear roles has not been perfect. After the Nationals lost Michael Morse for roughly the first half of the season, Johnson has not settled on a primary left field. DeRosa started six games, Nady eight and Bernadina two.

Johnson could not turn the position into a strength with those players, but that is not his view. His uncertain approach, he says, led to Nationals’ left fielders hitting .100/.217/.334 this year.

“I kind of had a wishy-washy approach to the left field situation,” Johnson said. “I need to get DeRosa, Nady and Bernie going. Find something that they can get their teeth into.”

Johnson frequently talks about getting hitters going, as if the only impediment to their success is his managing. He constantly searches for small, subtle ways to inject confidence into his players.

Sunday morning, as rain pelted the Nationals Park diamond and the radar called for unrelenting miserable weather, Johnson posted a lineup, anyway. Hitting third and playing third base was Tracy, who had gone hitless in his past 11 at-bats. Would Tracy have been in the same spot on a sunny day? Who knows? But for one morning, the bench player could glance at the lineup card and feel like a No. 3 hitter.

The day before, the Nationals scratched Zimmerman at the last moment when he felt inflammation in his right shoulder. About 15 minutes before the first pitch, DeRosa learned he would play. DeRosa had gone 2 for 26 on the season, but Johnson simply slid DeRosa into Zimmerman’s spot — batting third and playing third base — and he went 1 for 4.

“Hey, I was hitting .070 yesterday and he batted me third,” DeRosa said Sunday, laughing. “He’s my guy.”