Mariners Prospect Primer: System restocked

Some players are on the verge of stardom, others are entering a crucial phase of their development and still others are getting their first tastes of full-season ball. With the 2019 season approaching, MiLB.com takes a look at the most intriguing prospects from each MLB organization.
Full-season debutant: Jarred Kelenic, OF
Perhaps the most prized piece of the Mariners' considerable offseason prospect acquisitions, last year's Mets first-rounder has settled into his new surroundings courtesy of some advanced familiarity between player and team.
"We had had a workout for him before the Draft and we felt that he was arguably the best player in that Draft," Seattle's director of player development Andy McKay said. "Obviously other teams thought very highly of him too, based on where he was taken. We had zeroed in on him as a guy that we really wanted and he hasn't disappointed. He's exceeded every expectation that we've had for him for [Spring Training]. He's clearly a guy that has a tool set that separates him from many of his peers."

Kelenic saw action in the Rookie-level Gulf Coast League and Rookie Advanced Appalachian League last year and batted a combined .286/.371/.468 with six homers and 42 RBIs in 56 games. His well-rounded profile excites Seattle.
"It's nice as a player when you have multiple avenues to impact the game, whether it's with your defense or whether it's with your speed or your ability to hit or power or being a great teammate and making other people around you better," McKay said. "He certainly has that ability right now to impact games in a lot of different ways."
The 19-year-old will get every opportunity to climb the ladder in the middle of the field defensively.
"He'll be anchored in center field, but will certainly get reps in both corners just for his own development. Right now, he's going to play center field until for some reason he shows us he can't."
Breakout prospect: Justin Dunn, RHP
Acquired with Kelenic, Dunn reached Double-A last year but could be poised to assert himself as a soon-to-be big leaguer with another strong season.
"We got a kid who is very mature," McKay said. "He really knows how to work. He understands what it takes to put together a routine for four days to get ready to pitch. He knows how to compete, and he's very athletic.
"You like those things."
Dunn already boasts a 60-grade fastball and 55-grade slider, but is still working on developing his secondary arsenal.

"We are all learning about pitch design and it really is kind of a limitless pursuit," McKay said. "If a pitcher really wants to put in the time and the effort, I think we have tools in place now that you can develop pitches in ways that you really couldn't do before. Whether it's learning how to sink it a little bit more or cut it a little bit more or ride it up in the top of the zone a little bit more or add a cutter or shape your breaking ball a little bit differently, the tools are in place to take advantage of that."
Major League-ready: Justus Sheffield, LHP
Traded for the second time in his career in November, Sheffield's latest deal might be his last. The southpaw pitched four scoreless innings in big league Spring Training and allowed just one hit, striking out six and walking just one. Sheffield needs some fine-tuning in Triple-A, but combined between two stops in the Minors last year, the lefty went 7-6 with a 2.48 ERA and 123 strikeouts in 116 innings spanning 25 appearances. If he stays healthy and gets off to a hot start with Tacoma, Sheffield could be a member of the big league rotation before June.

Shining star: Evan White, 1B
White was already one of the best defensive first basemen in the Minors when he entered the Mariners organization, but his bat is coming along impressively as well. The Kentucky product batted .303/.375/.458 with 11 homers and 66 RBIs in 120 games for Class A Advanced Modesto last year.
"He's shown us consistently that he hits the baseball really hard," McKay said. "Not only does he consistently give you real good exit velocity, you see it in the weight room. His ability to create force is there, so it's not a fluke. He has the ability to mishit balls and hit them very hard. He's in a place right now where the last six, seven weeks of the season last year, he was able to get the ball up in the air a bit more. That's something we'll continually try to do with him. As unique as the skill set is -- right-handed hitting, left-handed throwing first baseman who can really run -- it's hard to come up with a comp for him."

Having conquered the California League, White will move up to Double-A this year for his first taste of the upper Minors.
"He's shown the power," McKay said. "He's shown the hit tool. I've said it before, he's going to win a Gold Glove in the big leagues, and he's an amazing person who everybody enjoys being around. He makes people better."

At the crossroads: Kyle Lewis, OF
Just three years ago, Lewis was the 11th overall pick in the Draft after winning the Golden Spikes Award at Mercer. Now he's entering what the Mariners hope will be a breakout year. After being dogged by injuries during his debut season and 2017, Lewis played in 86 games a year ago. Following a solid 260/.303/.429 showing in 49 games with Class A Advanced Modesto, though, he scuffled to a .220 average and .680 OPS with Double-A Arkansas. A healthy season and offseason have been huge steps for Lewis. Perhaps now he'll be settled enough to capitalize on his still impressive ceiling.
More to keep an eye on: Second baseman Shed Long will get looks around the infield, and McKay is confident he could handle outfield work too. "We've completely embraced everything about him and his game right now, so we'll see how it continues to evolve, but we're excited to have him," he said. … Young outfielder Julio Rodriguez OPSed .929 in the Dominican Summer League last year and should get his first taste of ball stateside this season at just 18. … Right-hander Sam Carlson underwent Tommy John surgery in July and could miss the whole season if the Mariners choose to play his return conservatively. … Dom Thompson-Williams belted 22 homers and swiped 20 bases between two Class A levels last year in the Yankees system before joining the Mariners in the November trade that also netted Sheffield.
Most home runs in the system:Joey Curletta, OF
Most stolen bases: Kelenic
Most strikeouts: Dunn
Current prospect to get most Major League playing time: Sheffield
Non-Top 100 prospect to end 2019 in the Top 100: White