Tanner Roark was tired of it all: The unlucky hops driving up his ERA, the scouting reports that complicated the game, the pitchers passing by him while he stayed at Class AAA. It all collected in his mind and bogged him down, until he could not hold it in anymore.

As the all-star break neared in 2012, Roark made another start in Syracuse. He had been in the Washington Nationals’ organization for three years, a right-handed pitcher acquired in an easily forgotten trade. He felt like he was just drifting. The first pitch of the game resulted in a bloop double over the drawn-in third baseman’s head. He knew he would lose again. Even when he did everything right, something went wrong.

“I got in my own head,” Roark said. “After that, it went downhill.”

Roark’s lowest moments in professional baseball cut a path to where he is now, at the start of a promising major league career. Thousands of players cycle through the minors, succumb to baseball’s subtle challenges and wash out before they see the majors, before they ever find out if they are good enough. The Nationals did not give up on Roark, and they refused to let Roark give up on himself. He changed his mental outlook. He kept going.

Roark emerged last year as a late-season call-up. Something odd happened whenever the unassuming, Midwestern right-hander climbed the mound: He got everybody out and the Nationals won. Roark’s dominance came in a small sample, but it was extreme. He went 7-1, and only two National League pitchers who threw at least 50 innings — back-end relievers Craig Kimbrel and Mark Melancon — posted a better ERA than Roark’s 1.51.

After a disappointing season last year, the Nationals have made some big changes, but Thomas Boswell thinks the newfound maturity of the players will keep them from repeating last year's mistakes. (Whitney Leaming/The Washington Post)

This spring training, Roark, 27, will compete for either the last spot in the Nationals’ starting rotation or a long relief position.

“For me, he’s a success story,” said Tony Beasley, Roark’s manager in Syracuse. “Because he wasn’t necessarily on the radar. Last year had to be what he dreamed about. Now, no matter what happens, he knows he can pitch at this level. I never see him going backwards.”

Sitting at his locker early this spring training, Roark called 2012 “my mental year.” He finished the season 6-17. But he credits those trials for why he reached the major leagues. It began after that one start, right before the all-star break, when the thoughts in his head came pouring out. In a coaches’ conference room in Syracuse, Roark met with Beasley, director of player development Doug Harris and Syracuse pitching coach Greg Booker.

“I felt good to get it off my chest and talk about it, and not just keep it inside,” Roark said. “After that, I started turning it around not worrying about anything else but making pitches and doing what I can.”

They had all sensed frustration and doubt brewing inside Roark. He had a fastball that could hit 95 mph, but too often he didn’t trust it. He would over-think when he needed a big pitch.

“We believed in Tanner’s ability and his stuff maybe a little bit more than he did,” Harris said. “We saw how it could possibly play. We just wanted him to have the confidence to go out there and execute what he was capable of doing.”

His place in the organization bothered Roark, too. The Nationals had traded for him, along with another minor league pitcher, for Cristian Guzman in 2010. He had repeated Class AA, and in Syracuse, when he thought he might have a chance at a promotion, he would be disappointed.

“The times he was pitching well, someone else may get called up,” Beasley said. “You can tell what guys are kind of thinking. You can see their expression or body language. When you recognize that, I think it’s our job to make sure they don’t feel devalued. They can remain confident and think they do have a chance, either with this organization or elsewhere. The thing was to make him believe he was a major league pitcher. He believed it.”

The trio told Roark to stay calm on the mound. They told him to believe in his pitches. It took him a few starts, but Roark started to change. He would not try to make perfect pitches when behind in the count. He would attack hitters, not try to trick them with an off-speed pitch. In tight situations, Roark would step off the back of the mound and take a deep breath. He began to focus less on scouting and trusted his ability to read a hitter’s swing and adjust, one of his greatest strengths.

“I had an epiphany, I guess you could say,” Roark said. “I knew I got to control everything that I do, not everything that happened behind me.”

Roark could not erase his lousy record, but he finished 2012 well enough to earn a spot in big league camp last spring. The Nationals sent him down in their first round of cuts. “First of all,” Roark said, “I was nervous as hell.”

Back in Syracuse, Roark stuck to what made him successful. His biggest improvement came in his walk rate, which he cut from 2.9 per nine innings to a minuscule 1.7. In August, the Nationals called him up.

“It sometimes requires patience,” Harris said. “I think the industry as a whole gets caught up in the young player who can fly through a system. When you look at the all-rookie team last year, half of them were 25 or older. They make up a big part of your ballclub. We want to get the most out of every player we possibly can.”

Roark wants to earn the fifth starter spot — “just a pride thing,” he said — but would happily settle for a long relief position. His mind is free and he is a major leaguer, and he has no intention of going back.

“This has been my lifelong dream since I was 4 years old,” Roark said. “So let’s keep it rolling.”