Shortstop Ian Desmond, left, played 154 games in both 2010 and 2011. Second baseman Danny Espinosa, right, played 158 in 2011 and 160 in 2012. (John McDonnell/THE WASHINGTON POST)

Part of the fabric of a baseball player is the ability to trudge through an arduous season, the longest of all professional sports. This year, the Washington Nationals’ spring training schedule is 34 games, the regular season a marathon of 162 games (if there is not a tie for a playoff spot) and, should they reach the playoffs, they could play a maximum of 20 more games through the end of the World Series. That’s 216 games over the span of nine months.

The Nationals have two stalwarts in the middle of their infield, players who believe in playing as often as their bodies will allow. Trying to be ready to play 162 regular season games is a badge of honor both shortstop Ian Desmond and second baseman Danny Espinosa have worn proudly. Manager Davey Johnson often jokes that he has the hardest time persuading his two middle infielders to sit so that the team’s deep bench can occasionally play.

Desmond, 27, and Espinosa, 25, both still want to play as much as possible, but Desmond is relenting and learning to avoid wearing down his body. Had an oblique injury not claimed a chunk of his season, he would have played close to 160 games.

Espinosa, however, won’t let up. Over the past two seasons, no Nationals player has appeared in as many games as Espinosa, who logged 160 games last year and 318 since 2011, tied for seventh most in the majors.

“It’s not like an ego thing, ‘Oh, I play more than anybody else,’” he said. “It’s just like, ‘Why wouldn’t you play?’ ”

The Post Sports Live crew discusses whether Stephen Strasburg will throw more than 100 pitches in at least one-third of his starts this season. In his first year back after Tommy John surgery, he topped 100 pitches in only five of his 28 starts. (Post Sports Live/The Washington Post)

Only four of 1,284 players appeared in 162 regular season games last season. Prince Fielder, the indestructible first baseman who has unbelievably missed only one game over the past four seasons, appeared in all 162 games last season and another 13 in the postseason. He was joined by Baltimore center fielder Adam Jones and Chicago shortstop Starlin Castro, both of whom play demanding positions, and Ichiro Suzuki, who was in his 12th major league season.

Lower the threshold by only two games, and only 14 players appeared in 160 games, including Espinosa. In 2010 and 2011, Desmond played 154 games each season. Adam LaRoche, at 32, played 154 games last season. Ryan Zimmerman is the last current Nationals player to have appeared in all 162 games in a season. He played every game in 2007, his second full season in the majors.

Espinosa last season dealt with a shoulder injury, enduring a torn left rotator cuff originally diagnosed as just a bruise. He has said he probably wouldn’t have played through the injury, which affected his hitting, had he known the rotator cuff was torn. But now that he spent all winter rehabbing, he has said his shoulder feels stronger than ever.

Espinosa’s general philosophy is to play every day, or to figure out a way to get on the field every day, as he put it. Despite his strikeouts, his power and slick fielding make him a top-tier second baseman. When Desmond was on the disabled list last season, Espinosa slid over to shortstop, his natural position, and Steve Lombardozzi played second base.

“I enjoy playing,” Espinosa said. “There’s a reason I start. If I’m not in the game, I don’t feel that someone behind is going to do any better. I don’t care about the depth behind me.

“It’s not a personal thing,” he added. “It’s not a pride thing. I prepare myself in the offseason to get ready for the season so I can play every day. If I’m doing bad, I don’t want a day off mentally. A day of mentally? I think about it more. That’s the worst. If I’m doing well, why would you want the day off? Unless you’re hurt. I think there’s a difference that players don’t know hurt and playing with some dings. Everyone plays with dings, but certain people handle it better.”

Johnson, a former second baseman, admires the drive in his two middle infielders. But he has to find a way to appease his workhouse shortstop and second baseman while finding at-bats for Lombardozzi, Tyler Moore, Roger Bernadina and Chad Tracy.

In 2011, Johnson said it was important for him to get Desmond and Espinosa as much playing time as possible so they could get better. But now, “it’s time I can give guys a rest and I feel like the guys I’m replacing them with, there’s not going to be that great a dropoff,” he said.

Desmond is at a unique place in his career. A year ago, he was facing an important season to prove if he was the Nationals’ future at shortstop. He had endured a lowly 2011 season in which he was one of the least productive everyday players at the plate. Last year, he found comfort in his swing, abilities and confidence, and enjoyed perhaps the best all-around season for a shortstop in baseball.

“There’s times when teams, they don’t want to let other guys behind them play because they’re scared that they might take your job,” he said. “In the past, I would never let anybody play my position. . . . I trust the guys that are playing behind and I trust the organization. I don’t think anybody’s coming for me. There’s always somebody out there, but you know what I mean.”

Desmond admits that during his oblique injury that forced him to land on the disabled list for 25 games and later a hamstring tweak, he learned how to play smarter. While he believes in legging out every infield ground ball, there’s no need to push a balky leg muscle when it’s not a dire situation. If he’s dragging, he’s more willing now to step aside for a brief break.

“This is why I think we had success last year: There may be times when I’m tired, and just because I want to play 162 doesn’t mean I have to play 162,” Desmond said. “I know that [Lombardozzi] can come in and pick me up for a day. If I need a break, I’m not hell-bent on playing 162 games for the pride of playing 162 games. If I feel good and strong, and every day I get the field and I’m ready to go, then yeah, I wanna play every one I can.”