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Seattle Mariners Midseason Top 10 Prospects

The Mariners went "all in” this season, further decimating baseball’s weakest farm system to beef up the big league team for a postseason run. In addition to trading for outfield, first base and bullpen help, GM Jerry Dipoto dealt prospects to add to their international free agent pool in an aggressive effort to sign Shohei Ohtani before losing out to the division rival Los Angeles Angels for the services of the Japanese two-way star.

For the most part, both the offseason and in-season acquisitions are paying immediate dividends, with the Mariners holding a solid lead at the season’s midpoint for one of two American League wild card berths. The impact of losing veteran second baseman Robinson Cano to a PED suspension was softened by offseason acquisition Dee Gordon, who moved from center field back to his natural second base position.

Gordon’s outfield spot was subsequently filled by the acquisition of veteran Denard Span.

The Seattle bullpen has been outstanding, anchored by closer Edwin Diaz who is on pace for a 60-save season. James Paxton included an early season no-hitter as part of a solid season at the front of the rotation. Lefty Marco Gonzalez’s step forward and a surprising performance by journeyman Wade LeBlanc has bolstered the rotation. 

Outfielder Mitch Haniger has been a revelation in the middle of the batting order a year after being acquired from Arizona along with equally effective shortstop Jean Segura. And, of course, ageless wonder Nelson Cruz just keeps on hitting.

Seattle will undoubtedly be buyers at the trade deadline, most likely looking to add starting pitching depth as well as a better-hitting catcher to pair with starter Mike Zunino. It’ll be tough to make any significant deals without further weakening the farm system, but DiPoto has never hesitated to make the necessary short-term moves. So with a postseason berth in view, he’s not likely to stop now.

1. Kyle Lewis, OF
High Class A Modesto
Age: 22

Lewis did not see game action during spring training and was held back in extended spring training until the second week of May to give his surgically-repaired knee time to strengthen. Returning to high Class A Modesto, Lewis has shown explosiveness in his legs and moves around the outfield well. At the plate, he is balanced and short to the ball, with loose hands and the ability to adjust to fastballs in the zone. He’s played mostly center field this season, but opinions that he’ll eventually move to right field, where his average or better arm will play, are becoming more prevalent. Lewis will continue to be watched closely to see if the knee can hold up for a full season, but for now the signs are positive.

2. Evan White, 1B
High Class A Modesto
Age: 22

Except for a brief four-game stint with Triple-A Tacoma, White has teamed with Kyle Lewis in the heart of the Modesto order. The 2017 first-round pick is a smart hitter who consistently has a plan when he’s in the batter’s box. Noted as more of a line drive hitter with an opposite field-approach, White is coming off a hot June in which the home run pop has emerged. He’s a plus defender at first base with acrobatic movements around the bag.

3. Logan Gilbert, RHP
Short-season Everett
Age: 21

Gilbert was Seattle’s first pick in a college-heavy 2018 draft after the righthander pitched 112 innings in his junior year at Stetson. At 6-foot-6, 225 pounds, he projects as future workhorse in the big league rotation, using a heavy, power fastball with good extension and life, and a breaking ball that the Mariners see as a plus offering. Since he’s already had a heavy college workload, the priority for the start of Gilbert’s pro career is to prepare him for next season.

4. Julio Rodriguez, OF
Rookie level DSL Mariners
Age: 17

The jewel of Seattle’s 2017 international class stayed on the island to begin his pro career in the Dominican Summer League, where he is hitting .319/.422/.462 through the end of June. A smart hitter with plus-plus raw power and a plus arm in right field, Rodriguez will likely get a bump to the Rookie-level Arizona League before the end of the summer.

5. Braden Bishop, OF
Double-A Arkansas
Age: 24

Bishop is following his strong 2017 season with a solid year at Double-A Arkansas after overcoming a slow month of April. He continues to get stronger, allowing him to better impact the baseball, and he has already surpassed his previous season high in home runs with seven long balls through the end of June. Regardless of how he hits at higher levels, Bishop’s plus-plus defense will earn him major league time before too long.

6. Noelvi Marte, SS
Not yet assigned
Age: 16

One of the top infield prospects in the 2018 international class, Marte signed with Seattle for a $1.55 million bonus on July 2. A natural hitter with a compact stroke, Marte has a track record of getting on base and hitting for power in games. He’s athletic and a plus runner underway with the chance to stay at shortstop long-term, depending on how the body develops with maturity. Like Rodriguez, Marte will likely start his pro career next summer in the Dominican Summer League.

7. Josh Stowers, OF
Short-season Everett
Age: 21

Selected by Seattle in the second round after a three-year college career at Louisville, Stowers has started strong at short-season Everett. He’s extremely athletic and is an above-average runner with top-of-the order skills. Stowers is playing his natural center field position to start his pro career and has plus instincts there. While his arm is no more than a fringe tool, the Mariners believe that Stowers’ instincts and athleticism will allow him to stay in the middle of the outfield.

8. Sam Carlson, RHP
Rookie level AZL Mariners
Age: 19

Seattle’s second-round pick in 2017, Carlson saw limited action with only two appearances in his first summer as a pro. Elbow and forearm tenderness kept him off the mound since then, but he was recently throwing bullpen sessions with the goal of pitching in Arizona League games by July. Instead, Carlson had Tommy John surgery and will be out until likely the 2020 season.

9. Matt Festa, RHP
Double-A Arkansas
Age: 25

Festa’s season got a slightly late start due to a hip flexor issue, but since then he’s been an effective cog in the Double-A Arkansas’ bullpen. His fastball has been 92-94 mph, with a plus slider being his money pitch. He should get to Triple-A before the end of the summer and it’s not unreasonable to envision him helping out in the Mariners’ bullpen late this season.

10. Seth Elledge, RHP
High Class A Modesto
Age: 22

Elledge fits the profile of many of the hard-throwing arms from Dallas Baptist. The 2017 fourth-rounder hasn’t disappointed in his first full season, posting a miniscule 0.93 ERA with 42 strikeouts in 29 innings through the end of June. The fastball comes out hot, sitting 90-95 mph with the possibility for more velocity in the future. His best secondary pitch is a sharp slider, but he needs to improve the command and control of all three of his pitches.


Logan Gilbert Primed To Make MLB Debut

The Mariners envision the 23-year-old righthander pitching in the big leagues in 2021, but they are mindful of his workload.


  • SS Bryson Brigman, Seattle’s third-round pick in 2016, was noted for his speed and athleticism and not much else during his first full season. But improved focus, better swing mechanics and playing with more confidence has resulted in a breakout season at high Class A Modesto for the San Diego product.
  • 3B/1B Ryan Costello, regarded the sleeper of the Mariners’ 2017 draft, just keeps on hitting—both for power and average at Low Class A Clinton. The 31st-round pick from Central Connecticut has officially put himself on the prospect radar.
  • RHP David McKay was one of four minor league pitchers acquired from the Royals during spring training in a cash transaction to bolster a thin corps of minor league pitching. Coming off a lackluster 2017 season split between the Royals’ low Class A and Rookie-level teams, McKay has used his sinking fastball and three-pitch mix to zoom through the Mariners’ system, posting an impressive 13.6 strikeout rate over three levels.


  • RHP Max Povse ranked as Seattle’s No. 6 prospect coming into the season, but after failing to earn a big league job during spring training the wheels came off in Triple-A. He struggled to maintain his release points, which resulted in an 8.84 ERA with Tacoma. Povse is attempting to right the ship at Double-A Arkansas.
  • 3B Joe Rizzo hasn’t built on a strong finish at high Class A Modesto in 2017, with his bat lacking impact to go along with ongoing questions as to whether he can stay at third base.
  • 2B Joseph Rosa was coming off a strong 2017 season at short-season Everett when he posted a .905 OPS, but the versatile switch-hitter hasn’t recovered from a slow start in his first extended taste of full-season ball with low Class A Clinton. 


  • OF Kyle Lewis stayed behind in extended spring training until the second week of May to continue strengthening the knee that required surgery after a collision at home plate in his first professional season.
  • RHP Art Warren ranked among the organization’s top 10 prospects after a strong 2017 season, but a nagging shoulder injury has kept the 25-year-old reliever off the mound for much of the season.
  • RHP Sam Carlson made two starts in Rookie-ball shortly after the Mariners picked the Minnesota native in the second round in 2017, but he’ll likely not pitch again until 2020 after continued forearm and elbow tenderness turned into a need for Tommy John surgery.


  • RHP Chasen Bradford, an offseason waiver claim from the Mets, has been a solid contributor to the major league bullpen. He’s 5-0, 2.65 in 30 appearances.

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