SEATTLE -- First impressions can be difficult to overcome, which is why many Mariners fans will be surprised that center fielder Mallex Smith has improved so dramatically that he ranks among the best defenders in the Major Leagues at his position this year in some metrics.

Remember when Smith was so out of kilter in the opening month of the season that even routine plays became an adventure and the Mariners wound up sending him down to Triple-A Tacoma to regain his confidence both at the plate and in the field?

Smith has not only overcome that shaky start, he ranks seventh among all MLB outfielders in Statcast’s Outs Above Average metric that looks at the catch probability and number of balls tracked down, trailing only Victor Robles of the Nats, Kevin Kiermaier of the Rays, Lorenzo Cain of the Brewers, Byron Buxton of the Twins, Delino DeShields of the Rangers and Harrison Bader of the Cardinals.

Of all the Mariners’ transformations this year, Smith’s defense stands among the most dramatic.

Manager Scott Servais believes the right elbow strain that wiped out Smith's Spring Training led to the youngster pressing too much to prove himself to his new team after he finally joined the club when it got back from the Opening Series in Japan. And one misplay led to another as the pressure mounted.

“I give him a ton of credit,” Servais said. “He really has played solid defense here the last three-quarters of the season. It’s been really good. He’s been able to finish plays. Mallex was getting to a lot of balls early, he just wasn’t finishing the play. Balls would tip off his glove and what not.

"And that’s [turned around] just because of hard work. He didn’t bury his head in his locker and feel sorry for himself. He just said the only way out of this is to work through it. He did a really nice job there.”

Smith has worked with outfield coach Chris Prieto nearly every day since rejoining the team in May, hitting the field early as Prieto lines ball after ball at Smith to sharpen his reaction time or launches drives up against the fence to make those plays come naturally as well.

“Mallex comes and gets me every day and enjoys the process of working,” Prieto said. “It’s built some confidence for him, so it’s been nice to see. When we first started doing that line drive drill, it was kind of nerve-wracking for him. It was really fast-paced and hard, and he’s gotten better.

“If you watched from the beginning until now, I’m so impressed with how under control he is and his glove moves much more confidently. It’s been good to see. And he sees and feels how much better it makes him, so that’s why he comes and finds me every day. He needs to do it. It’s part of his routine now.”

Smith said putting in the extra work with Prieto is a no-brainer.

“If you want to get better at something, you’ve got to work at it,” he said. “That in itself means something to me. Getting better matters. Feeling better and playing better gives you a lot more confidence. That’s really what it’s about. Going out there every day is about being comfortable when the game starts. We can simulate the hardest balls I have to field and make plays on, then I can translate that into the game.”

Smith leads the Major Leagues with 45 stolen bases and that elite speed allows him to track down balls in the gaps as well. He made a 5-star catch -- the most difficult play on Statcast’s ratings -- look easy on Sept. 7 in Houston when he hauled in a José Altuve drive on a play estimated at just a 5 percent catch probability.

He made another outstanding catch to rob Zack Collins of the White Sox before crashing into the T-Mobile Park fence on Sept. 13.

But Prieto said Smith isn’t just relying on his athleticism, as he studies opposing hitters to know where to position himself before each pitch.

“He reads the heat maps of opposing teams and gets on the same page with me before the game,” Prieto said “He wants to know where to play guys, in hitter’s counts and behind in the count. He takes charge and moves guys around. Very rarely will I override him because he studies so well.

“It’s been really nice to see the transformation from the beginning of the season until now. He’s done so many little things that go kind of unnoticed that really have helped him out.”