GLENDALE, Ariz. — In one quick and powerful swing, Mitch Haniger offered a hint as to why the Mariners have handed him the starting right field job for the 2017 season. Beyond that one swing, the 26-year-old Haniger has also provided daily verification with his focused preparation and mature practice habits.

Facing White Sox fire-balling phenom Michael Kopech in his first at-bat of Tuesday’s Cactus League game with Robinson Cano on third and Nelson Cruz on second, Haniger fell behind 0-2 in the count and seemed destined for a strikeout.

But the 20-year-old Kopech made a mistake, leaving a slider up in the zone on his third pitch of the at-bat.

In a stance and swing eerily reminiscent of Toronto slugger Josh Donaldson, Haniger took a big step with his front foot, loaded his hands and unleashed on the cookie of a pitch, sending a rocket to deep left field. The ball carried over the wall, then the visitor’s bullpen in left field, over the uninhabited patio area and out of the boundaries of the field at Camelback Ranch. The ball hit on a walkway behind the stadium and bounced up against the Dodgers’ office building behind the park.

The prodigious blast carried well more than 400 feet.

“Definitely good to get the timing going and get synced up right,” Haniger said. “I was just trying to hit the ball hard. Today felt a lot better. I’m making progress, so I’ll just keep working hard in the cage and try to feel some things. So it’s good.”

Besides the homer, Haniger also had a stinging line drive into left field in his second at-bat.

“Nice to see Haniger get going,” manager Scott Servais. “He’s was a little slow to get going the last few days. Good day for him.”

Despite having just over 30 games of experience at the Major League level, the Mariners have made Haniger a part of their everyday lineup. He was a priority piece in the trade that also brought shortstop Jean Segura to the team. Since the November deal, Servais, Mariners general manger Jerry Dipoto and other members of the baseball ops staff have heaped praise on Haniger’s potential as an all-around player, who would provide some power, speed and defense. The comparison to late-bloom Angels’ outfielder Kole Calhoun was even mentioned by Dipoto.

“Mitch Haniger last year, by the numbers, simply was the best offensive player in the minor leagues at any level,” Dipoto said. “He produced more runs in WRC plus (weighted runs created-plus) than any other player.

Indeed, Haniger put up stellar numbers in 2016, earning the Diamondbacks’ minor league player of the year award. In 129 games combined between Class AA Mobile and Class AAA Reno, he hit .321 (147-for-458) with a .999 on-base plus slugging percentage, 34 doubles, five triples, 25 home runs, 94 RBI and 12 stolen bases in 129 games.

“He’s done what he can do at those levels,” Dipoto said. “He’s developed and polished.”

That polish has shown early in camp with his attitude and effort level during daily work on the field and in the weight room. Haniger attacks it with game-like intensity and the seriousness of a player trying to prove something to the world.

When asked which young player had impressed him most, Servais didn’t hesitate to say, “Mitch Haniger.”

“Very professional approach,” Servais said. “He knows what he’s doing. He has a plan every time he’s in the outfield, on the bases or in the batter’s box. He’s getting an opportunity to play here. He’s worked for it his whole life and we’re going to give it to him and let him run. He’s taking it very seriously, and I like what I see. He’s been very impressive.”

This isn’t some eyewash for his new teammates in big league camp. Haniger has built this approach over the years.

“I was like this even in minor league camp the past couple of years,” he said. “I think it’s gotten better and better each year. But it’s something I’ve prided myself on. When it comes down to practice time or lifting or whatever I’m supposed to be doing, I’m always very serious.”

Admittedly, there is some motivation stemming from his meandering path through two organizations to the big leagues. A first-round pick of the Brewers in 2012 out of Cal Poly-San Luis Obispo, he was traded to the Diamondbacks in midseason of 2014. After spending much of 2014 at the Class AA level, he was demoted down to the High A level in 2015 to play consistently. He was getting passed by on the Arizona organizational depth chart. It was there he decided to revamp his stance and swing in an effort to find some power.

“I did a ton of different things, but mostly changing my swing plane and getting on time with the pitch early and changing how I thought about mechanics before” he said. “I read a lot different articles about difference mechanical philosophies and what makes the most sense for me. “

The names and swings of Donaldson and fellow Diamondback A.J. Pollock became fixtures in his mind.

“I studied mostly right-handed hitters just because that’s what I am,” he said. “For the most part, they’re right-handed guys that aren’t ‘ginormous’ in size but produce a lot of power. Because that’s what I felt like I hadn’t been able to tap into in the past. And I knew I was capable of it. I think last year, I definitely started to break through.”

The process to power took time. He started with a bigger leg kick similar to Donaldson. And then after the 2015 season, he started to focus on his upper body and hand placement.

“The combination of the two opened things up,” he said. “And as each day went, I noticed progress. I was getting better from Day 1 and got better the next season. Last year, I was really clicking April, May and June and just kept going.”

It earned him a late call up to the big leagues, where he played almost every day in center field. He played in 34 games, hitting .229 with two doubles, a triple, five homers and 17 RBI. Just making the big leagues could be viewed as an accomplishment considering where he was to start 2015, but Haniger took no solace in it. He wasn’t pleased with his play in his debut.

“I’m really hard on myself and that’s not the best word, but I expect a lot out of myself so I feel like I really unperformed,” he said. “I feel like I’m capable of a lot more than I showed offensively and defensively. I think I’ve learned a lot. That was a great experience. This offseason I tried to fix some of the stuff I need to get better.”

It’s why he’s so focused this spring.

“With the stuff that happened with the D’Backs, going up and going down in my first full year that was a little rough, I think it gave me more of a chip on my shoulder,” he said. “I’ve always had one from the start, but I think that’s helped me a lot and learning from the failure.”

Haniger understands that there will be more failure.

“I just want to focus on what I can do to help the team win and whatever that role may be, I want to be the best at it,” he said. ” If prepare myself in the weight room and in the cage and during our practice time this way, the game results will eventually take care of themselves. I know there are going to be ups and downs, but as long as you stay consistent with the other stuff, that’s when you’ll be able to look back at the end and say, ‘I’ve had a good year.’