Andrew Stevenson (Jonathan Newton/The Washington Post)

WEST PALM BEACH, Fla. — About a month after he was hired by the Washington Nationals, Kevin Long hopped on a plane to Louisiana, a somewhat unorthodox route for a major league hitting coach in his first few weeks with a new team.

The roster he inherited includes MVP candidates Bryce Harper and Anthony Rendon; his devoted disciple Daniel Murphy; and budding star Trea Turner, but Long didn’t fly there to find any of them. He went there to find 23-year-old outfielder Andrew Stevenson.

Long flew around the country to meet with a few Nationals hitters before the season. He sought out some of them. The front office suggested others. Stevenson fell into the latter category — a project prioritized by the Nationals’ decision-makers.

“It’s definitely an honor,” Stevenson said. “To kind of have them want to get me to the next level, I’m very appreciative they wanted to do that for me.”

The Nationals selected Stevenson as their first pick, a second-rounder, in the 2015 draft out of LSU. Then, Stevenson was a defense-first, contact-heavy outfielder with a somewhat unorthodox swing. Evaluators inside and outside the organization projected him as a big leaguer, at least a reliable fourth outfielder, perhaps an everyday guy if he made progress.

Because of seemingly endless injuries to their big league outfielders, the Nationals had to rush him to the majors last season. He hit .158 in 37 big league games, which didn’t disappoint members of the front office. They knew he wasn’t ready offensively. He knew that, too.

“I kind of knew once I got up there, I had to make a few changes to be at the level I wanted to be,” Stevenson said. “I liked what [Long] had to say. It was at a good point in the year to make those changes so I would have the whole offseason to work on it.”

Stevenson always had a somewhat unorthodox swing and setup, so fundamental it was almost robotic — which isn’t necessarily a compliment when the best left-handed swings are often described as “sweet” or “smooth.” Instead of one fluid motion, Stevenson swung in parts, resulting in a swing that looked textbook but lessened his ability to drive the ball. That swing did enough to get him to the majors, but it did not seem powerful enough to keep him there.

“I always kind of thought I had more power in there somewhere in my body, so it was just kind of finding it, staying in my legs instead of coming out of them,” said Stevenson, who has homered once in 12 games this spring after homering twice in 136 games over three levels last year.

Long felt most of his players didn’t require personalized visits. Any changes he wanted to make to the swings of the more established big leaguers could be made in spring training. But the substantial changes he wanted to make to Stevenson’s swing, particularly how Stevenson used his lower half, would require time to set.

So Long flew to Louisiana for two days of intense training — a lot of swings, a lot of suggestions. He would tell Stevenson, “I’d like you to try this,” or, “I think you should do this.” Stevenson would ask for the rationale. Long would provide it.

“I’d tell him what’s happening,” Long said. “‘You’re stopping your swing. You’re popping up, which means you have to smother the ball.’”

In old video of Stevenson’s swing, his legs contribute but do not drive him. He finishes his swing upright, his body weight moving up away from the ground instead of down through it. With a swing like that, only perfect contact — “smothering the ball” — yields power. With a more grounded swing, power comes more naturally.

Long helped Stevenson push off the ground to generate more power. He also urged Stevenson to follow through with two hands instead of taking one off the bat, to create the habit of finishing his swing more deliberately. After two days of drills, Long flew back home to Arizona and asked Stevenson to send him video as he tried to solidify the changes throughout the winter. According to Long, they stuck.

“You’ll see more explosiveness on the swing. He’s not necessarily trying to lift the ball, but his legs are working so good it’s allowing him to get the launch angle you want,” Long said. “We didn’t really focus on hitting the ball in the air. We focused on getting his legs into the swing. Everybody that’s seen him — minor league coaches, staff, everyone — they say he looks completely different.”

General Manager Mike Rizzo and his staff have indeed noticed a change. They see Stevenson driving the ball better, making the kind of changes they hoped he would make — the kind that, combined with his above-average defense and speed, could help him evolve into an everyday big league outfielder. One rival scout said he has already noticed Stevenson better incorporating his legs into his swing. Stevenson, who also added five pounds of muscle this offseason, said he feels a difference, too.

“I do [feel more powerful],” Stevenson said. “ … Staying in my legs, it’s trying to give myself more time. So I think I’ll be able to make a little better decisions at the plate. I think I’ll drive a few more balls in the gaps and maybe get a few more out this year.”

Barring injuries to more established outfielders, Stevenson won’t make the Opening Day roster. In fact, he could be sent back to minor league camp sooner rather than later. As veterans take more and more at-bats, fewer at-bats remain for Stevenson, and the Nationals want him to get as many repetitions as he can.

Long is best known for helping major league hitters evolve into much better major league hitters — see Murphy for a telling example. But here, with the Nationals, one of his first projects was a young outfielder with a bright future that might already be brighter because of a few days of work during the Louisiana winter.

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