Ketel Marte thought he knew it all. He was young, just 21 when he reached the big leagues, and after tasting success as a rookie, he no longer thought he needed to listen. Marte, thinking back on his days with the Seattle Mariners, is not proud of this.

“I was a little crazy out there,” he said.

On Friday, for the first time since being traded to the Diamondbacks almost two years ago, he will face his old team, and he needed only a moment to consider the question: How is he most different now compared to what he was then?

He considers himself a stronger hitter, a more consistent defender, all of that. But he thinks the biggest difference between the Marte the Mariners last saw and the player he is today starts between his ears. And with what he’s willing to let in them.

“When I was there, I thought, ‘Oh, I’m Ketel Marte, I’m hitting good. I know what I’m doing, so I don’t listen to anybody,’” Marte said. “A couple of players would try to talk to me about it, but I wouldn’t listen. I’ve learned about that. I’m a better player now. I’m better, I’m smarter, because I listen. When somebody comes to me and says, ‘Hey you need to get better at that,’ I try to do it.”

In his first full season as a Diamondbacks regular, Marte, 24, has showcased a well-rounded game. His season started slowly at the plate, but he has compiled respectable offensive numbers, particularly for a middle infielder.

He is hitting .249/.322/.415, and with 20 doubles, 10 triples and 10 homers. He is the only player in baseball this season to have reached double digits in all three categories, something only Steve Finley, Stephen Drew and David Peralta have done in a season in club history. He also has played solid defense at second base.

Marte is hardly the first player in baseball to think he had it figured out. But what he can’t seem to point to is why his mindset changed.

Perhaps it was struggling through a rough, injury-prone 2016 season. Perhaps it was the shock of getting dealt as part of the Taijuan Walker trade, a swap that sent infielder Jean Segura, outfielder Mitch Haniger and pitcher Zac Curtis to the Mariners. Maybe it was getting sent to Triple-A Reno to start last season.

But Diamondbacks people say his attitude has been great since his first day of spring training last year, and they talk about how he was willing to make changes upon arrival.

Early on, hitting coach Dave Magadan noticed how inconsistent Marte’s hitting routine was. A switch-hitter, Marte wouldn’t always put in work from both sides of the plate, and the drills he did varied by the day.

“He was kind of all over the place,” Magadan said. “One day he’d do flips, the next day he was doing the tee, the next day he wouldn’t do anything. We tried to corral him and get him doing things consistently from both sides of the plate. Always doing stuff not just to do it, but so it can get you where you want to be.”

The rest of Marte’s daily activity was just as inconsistent. He would arrive at the park at different times, work out when he felt like it. He dealt with a string of injuries in 2016, and he believes they were a direct result of how ill-prepared his body was for the grind of a season.

“If you don’t take care of your body, you’re going to get hurt every time,” he said. “I hurt my hamstring, my knee, my ankle, my elbow – everything. It was because I didn’t work hard out there.”

Now, he says, he has a well-established routine. Most days, he gets to the ballpark at a set time and heads to the trainer’s room for treatment or a massage. From there, it’s off to the gym before heading to the cage for early work. Then he sits tight until the start of batting practice.

He credits Triple-A Reno manager Greg Gross and coach Mike Lansing for helping instill this work ethic in him last season, but Gross said Marte didn’t require much prodding. Though clearly disappointed about being sent down, Marte had the right attitude, Gross said, and he embraced the simple message Reno coaches gave him.

“If the attitude is, ‘I should be there (in the majors),’ it’s probably not going to work,” Gross said. “But from Day 1, he came in and he worked. He was, for lack of a better term, a model citizen.”

Marte made such a positive impression in his first year he was given a five-year, $24 million deal before this season.

Marte said he is excited to face the Mariners, eager to see old friends, including Robinson Cano, Nelson Cruz and Segura, whom he knew before they were traded for each other.

“I’ll try to do my best and try my best to beat them,” he said. “I’ll focus on that.”

His performance this year, though solid, still has the feel of a player scratching the surface. That, at least, is how Marte views himself: Even with the progress of the past two years, there’s still plenty more to come.

“I was younger, but now I’m getting old,” he said. “I’ve got to get better. That’s what I’m trying to do, learn one thing every day.”


Reach Piecoro at (602) 444-8680 or [email protected]. Follow him on Twitter @nickpiecoro.