SEATTLE -- In this step-back season for the Mariners, one of the young players stepping forward is shortstop J.P. Crawford.

The strong defensive play of the 24-year-old Crawford stands as a large positive among what has been an increasingly difficult season at the Major League level, where the Mariners are trying to tread water while waiting for promising prospects to mature in the Minors.

Crawford was one of the Major League-ready prospects acquired by general manager Jerry Dipoto last winter, but there were questions about his defense when he arrived from the Phillies in the five-player trade that sent Jean Segura to Philadelphia.

So while his bat has proven capable with a .248/.335/.414 slash line with four homers and 35 RBIs to go with five stolen bases in his first 57 games since being promoted from Triple-A Tacoma in May, it’s Crawford’s glove work that has brought smiles to the Mariners’ coaching staff.

Crawford ranks fifth among American League shortstops in Baseball Reference’s range factor per game behind only the Royals’ Adalberto Mondesi, the White Sox Tim Anderson, the Blue Jays’ Freddy Galvis and the Angels’ Andrelton Simmons.

Crawford’s arrival played a huge part in stabilizing the Mariners’ shaky early-season infield defense as he’s committed just seven errors in 492 1/3 innings after Tim Beckham’s 12 miscues in 344 1/3 innings at that position.

That’s a remarkable improvement for Crawford, who made eight errors in 229 2/3 innings last year at shortstop in Philadephia, where his erratic throwing was an overriding concern that limited the Phillies’ faith and ultimately led to their willingness to trade their 2013 first-round Draft pick.

All eight of his errors in Philly came on throws, while he’s made just one throwing error this season after hooking up with Mariners infield coach Perry Hill prior to Spring Training.

How far has he come?

“Leaps and bounds,” said the 67-year-old Hill, who is renowned for his fundamentals work. “It’s a credit to him. He’s done everything we’ve asked and mastered a lot of the skills we talk about. He’s a front-line shortstop.”

Crawford always had the arm strength, but his footwork was the problem, according to Hill, who says an infielder’s feet control the upper body and how a player aligns himself for throws.

“You could hit him the same ground ball and he’d do something different with his feet all the time,” said Hill. “We sat down in Arizona, met a couple weeks before Spring Training and just discussed it. He said he’d buy in and went to work. He’s made tremendous progress. Not too many have the work ethic he has. He’s really busted his butt to get better.”

Hill, in his first year on manager Scott Servais' staff, has helped a number of players win Gold Gloves during his lengthy coaching tenure. Mariners second baseman Dee Gordon sung his praises from the start, having worked with Hill with the Marlins earlier in his career, and his teammates quickly jumped on board.

“Perry has helped me so much throughout this year,” Crawford said. “I feel like I can compete with the best of them on defense now, thanks to him. We just go out and work every day. It’s little, simple stuff and it works. Without him, I don’t think I’d be here.”

Crawford has been outstanding on the routine plays, which is what Hill emphasizes. And he’s proven capable of the unexpected gems as well, including what has to be the Mariners’ defensive play of the year so far, with his diving stop deep in the hole in the ninth inning of a 3-2 win over the Tigers on July 26.

Not only did Crawford glove the 100 mph ground ball by Jeimer Candelario, he then pulled off an off-balance, across-his-body throw without ever planting his feet to nip the runner at first for the final out and set up a walk-off win.

First baseman Aaron Nola said it looked like an Hakeem Olajuwon hook shot coming over the top from Crawford, and even the veteran Hill was shaking his head afterward.

“Mercy. That was one of the best plays I’ve seen, and I’ve been around awhile,” Hill said. “Just the athletic ability and everything about it. I always tell these guys that I want you to make the [standard] plays all the time. Those are the plays we work on, that are structured and fundamental. Outside the box, be an athlete. He was outside the box on that one, and he was an athlete.”

For once, Crawford didn’t set his feet and make the fundamentally sound throw across the diamond. But he got no grief from his coach this time.

“He didn’t need his feet or his eyes on that one,” Hill said with a chuckle. “I had no idea when he threw it. I thought, ‘Where is this going?’ And it went right to [the first baseman]."

The only one seemingly unimpressed was Crawford, who believes his newfound consistency should carry over even to the spectacular.

“That’s a play I should make,” he said. “It’s something I know I can do and should be doing every night.”

The Mariners, of course, would be just fine with making all the normal plays and continuing to progress. One step forward at a time.