Will Tanner Roark crack the Nationals’ rotation in 2016? (Katherine Frey/The Washington Post)

VIERA — Washington Nationals pitcher Tanner Roark expects to start this season. He said that without hesitation Thursday, standing at his locker as fellow pitchers reported to spring training around him.

A few lockers down, a tall, skinny man with long blond hair unpacked his things. That guy, Bronson Arroyo, seems like the only unknown variable with the power to throw off the math, a veteran coming off an injury who could make the rotation with a big spring — and in so doing push either Roark or Joe Ross out. But Roark has been preparing to start and will continue to do so, a former 15-game winner eager to stop sliding between roles.

Last year, when he got bumped from the rotation and into the bullpen, he found extra velocity but lost command, and never recovered his old form.

“It was just, I think, a big learning experience,” he said. “A mental (thing), which is always a good thing to have. You always can be mentally sharper, because this game can wear on you, and you want to be as mentally sharp as possible. It helps you build up, I guess, your tolerance for some things that you might not like and you have to deal with regardless.”

Beyond the mental aspect, and beyond the logistics of bullpen life, Roark said he learned the importance of pitching his way. The added adrenaline of bullpen duty, combined with the fact that he threw far fewer pitches relieving than he did starting, helped Roark find a few extra miles per hour of velocity last season. He doesn’t normally look back at the radar readings on the scoreboard, he said, but one time he did, and saw 96. He started overthrowing.

“I started doing that at the beginning, because my arm felt great and I wasn’t pitching every fifth day and throwing 90-100 pitches or whatever. So coming in and thinking I could blow it by everybody — not pitching for location and letting my two-seamer work,” Roark said. “It was really messing me up.”

So Roark learned to pitch his way, letting his two-seamer run and mixing pitches, a practice he hopes to revive as a starter this season. He’ll work on it under the eye of new pitching coach Mike Maddux, who was the major league pitching coach in Texas when Roark was in the minors there, though they didn’t cross paths much then.

A few months ago, at Winterfest in D.C., Maddux said a starting spot is Roark’s to lose. Roark expects to keep it.

>>>> The Nationals agreed to terms with right-handed reliever Burke Badenhop Thursday on a minor league deal with an invitation to spring training.

Badenhop is 33 years old, and appeared in 68 games for the Reds last season. He pitched in 70 games for the Red Sox in 2014, and maintained a 2.29 ERA with a 2.11 strikeout-to-walk ratio. He is more reliant on groundballs than overpowering hitters, as his fastball sits in the high 80s.

Badenhop joins a long list of bullpen hopefuls, which got longer Wednesday when the Nationals signed another veteran right-hander, Matt Belisle.

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