Every day through the past winter, Danny Espinosa began the task of retraining himself the same way. He placed a ball on a tee, thigh-high. He stood in the left-handed batter’s box, the spot that had plagued him for much of two seasons. He grabbed the bat with his right hand only, a necessity as a torn rotator cuff healed inside his left shoulder.

Gripping the handle with only his bottom hand, Espinosa took 30 or 40 hacks. He aimed to hit groundballs “the right way,” he said, letting the barrel travel on a violent, direct path, the downward swing that escaped him as he established himself the past two seasons as the Washington Nationals’ everyday second baseman. The work continued until January, until Espinosa could swing with both hands again. By that point, he had remade his swing and regained his confidence as a left-handed hitter.

Espinosa’s defense, power, base running and durability last season made him one of the league’s most valuable second basemen. There may be just one skill preventing him from emerging as an elite player, and it happens to be baseball’s most elemental objective. He struck out 189 times last season, more than any hitter in the National League.

“I’m not going to think about it,” Espinosa said. “I think [strikeouts] will go down naturally, just by having a better swing. I won’t miss pitches. Of course I want them to go down. It’s embarrassing to strike out. But I think they’re going to go down naturally because my swing is a lot better.”

Both Espinosa and the Nationals believe changes to his swing will enable him to put more balls in play, strike out less and repeat the kind of leap shortstop Ian Desmond made in his third full season — from a player who flashes his considerable ability to an all-star who shows it consistently.

On Tuesday, Espinosa whacked two sharp, line-drive singles from the left side; he dropped a bunt in his only other plate appearance. Spring training results possess scant relevance, but there is this: Espinosa struck out five times in his first 14 at-bats this spring, which he attributed to rusty timing. He’s whiffed only twice in his past 12 plate appearances. Overall, he’s 8 for 25 (.320) with a double.

“He knows who he is,” Manager Davey Johnson said. “He knows what he needs to do. Espi reminds me of being about where Desi was a year or so ago.”

Desmond and Espinosa are not identical. Desmond had shown he had all the pieces, but had not brought them together until last year. Espinosa is already a complete picture, with one blemish to be removed. But Desmond, too, can see the similarity.

“Everyone is different,” Desmond said. “But at the same time, he’s shown signs of everything he can do. He’s hit big home runs in pressure-packed situations. He’s played unbelievable defense. He’s done it all. Now it’s just got to be about that consistent basis. The more you play, the more consistent you get. It’s as simple as that. So, yeah, I see Danny having a big year. He’s got his head in the right place. He’s going to be a superstar, no doubt.”

Espinosa derives his confidence from experience. From early August to late September, he clobbered the ball. He hit .293 with a .352 on-base percentage and .463 slugging percentage over a 43-game stretch, more than a quarter of the season.

During the streak, Espinosa landed awkwardly diving for a ball in Atlanta. He masked the pain with a cortisone shot, and he never revealed the severity of the injury: a torn rotator cuff in his non-throwing shoulder. His numbers nosedived in the season’s final week and, in the NLDS against the St. Louis Cardinals, he went 1 for 15 with seven strikeouts.

“I tried playing through it. It didn’t work,” Espinosa said. “But I’m not going to make any excuse for what it was. . . . Whatever happened, whether it be my shoulder or whatever, I kind of lost my swing then.”

Now, in the spring, Espinosa will not dwell on the end of his season. He goes back to when he played his best, viewing it as an assurance of what will come.

“I know I can do it,” Espinosa said. “I’m very confident in my ability. The last couple years have been up and down with my swing left-handed. I feel great now.”

The change has not come overnight. Hitting coach Rick Eckstein has worked with Espinosa to alter his mechanics for the past two seasons, as he struck out in 27 percent of his plate appearances. Batting right-handed, Espinosa used a compact swing, like Eckstein wanted him to.

Hitting lefty, Espinosa took a different approach, letting the pitch travel deep into the strike zone, trying to shoot liners the other way. Rather than attacking the ball, he would dip his back shoulder. The first move his bottom hand made was up, not down toward the ball.

His swing became long, which made him susceptible to inside fastballs. He started rushing to keep up, and then pitchers carved him up with off-speed pitches. “When my swing was bad, I was trying to cheat because my swing was long and I was dropping my hands real bad,” Espinosa said. “That’s when I got into a lot of problems.”

“He was working on it,” Eckstein said. “There was no question about it. His entire life, he was thinking a certain way. Things take time to develop, and the mentality takes time to really understand. That’s probably the biggest leap that I’ve seen from him. He understands what he wants to do, and he’s committed to it. And it’s very exciting to think where he’s going now.”

Eckstein expects Espinosa’s improved approach to help his plate discipline, too. Last year, Eckstein said, dropping his back shoulder caused Espinosa to lower his head. When that happened, high pitches looked like strikes. With his downward-angled path, Espinosa’s eyes should instead stay focused on his strike zone.

“He’s obviously a pivotal guy in our lineup,” Eckstein said. “Being out there every day and what his ability level dictates, he knows that he has the ability to put the ball in play. When he understands how he’s going about it, and then also keeping himself in the areas that he’s good at, he’s gonna cut down on his strikeouts.”