2021 Seattle Mariners Midseason Top 30 Prospects Update

A funny thing happened to the Mariners in the middle of their rebuild: They started winning.

The Mariners entered the week of the trade deadline with a 54-46 record and only 1 1/2 games out of an American League wild card spot. While RHP Logan Gilbert, OF Jarred Kelenic and C Cal Raleigh made their debuts this season, most of the team’s success has unexpectedly been driven by players who were already in Seattle. 

A healthy return from OF Mitch Haniger and steps forward from SS J.P. Crawford and LHP Yusei Kikuchi helped the Mariners win sooner than expected, and they stand to gain significant reinforcements from their farm system in the coming years. The progress of OF Julio Rodriguez, RHP George Kirby and SS Noelvi Marte in particular has helped elevate the Mariners’ farm system to an elite tier, which bodes well for their chances of ending the longest playoff drought in North American sports relatively soon.

The Mariners have already tried to toe the line of buying and selling simultaneously at this year’s deadline. They traded popular closer Kendall Graveman to the division-rival Astros in a stunning move that angered the team’s players, then turned around and acquired lefthanded starter Tyler Anderson from the Pirates for two prospects. 

General manager Jerry Dipoto will have to tread lightly. A compulsive trader whose deals have overwhelmingly been neutral in his career, he now has to be pickier about the trades he makes in order not to short-circuit a winning team. The Graveman trade was not a promising start, with one Mariners player characterizing Dipoto to the Seattle Times’ Ryan Divish as someone who “sits up in his suite, playing fantasy baseball and rips apart our team without telling us anything.”

With a winning record in the majors and a burgeoning farm system, things are beginning to look up in Seattle. Whether Dipoto can pull the right levers to make it all come together remains to be seen.

Top 10 Prospects

1. Julio Rodriguez, OF
Age: 20. Team: Double-A Arkansas

Rodriguez hit his way out of High-A Everett after just 28 games, led the Dominican Republic to the Olympics and raked once he arrived at Double-A in late June. He improved the quality of his at-bats, was more consistent from game-to-game and proved he can handle upper-level stuff, cementing his potential as a franchise-caliber player. The only knock on Rodriguez is his occasional lack of focus on defense results in avoidable mistakes, but he has the physical tools to be at least an average defender.

2. Noelvi Marte, SS
Age: 19. Team: Low-A Modesto

Marte has been arguably the top player in the Low-A West despite being one of the league’s youngest players. He has demonstrated enormous power out of a smooth, easy swing, used the whole field and shown just enough defensively to have a chance to stick at shortstop. He has shown the actions, hands and first step for the position but is prone to mental lapses that will need to be cleaned up.

3. George Kirby, RHP
Age: 23. Team: High-A Everett

Kirby enhanced his arsenal while maintaining his plus-plus control, earning him future top-of-the-rotation projections. His fastball sits 95-99 mph with explosive late life that beats hitters at the top of the zone, his slider and changeup both flash plus and he locates everything to both sides of the plate. He also has a curveball that shows average, giving him the rare combination of elite velocity, a four-pitch arsenal and impeccable control. He missed most of July with shoulder tenderness, but there was no structural damage and he has resumed throwing.

4. Emerson Hancock, RHP
Age: 22. Team: High-A Everett

Hancock missed more than a month due to shoulder tenderness, but he was effective when healthy. He showed the ability to play his sinking 93-96 mph two-seamer and riding 95-98 mph four-seamer off each other, with the sinker the better of the two, and his slider has been an above-average to plus pitch. Hancock’s changeup and the quality of his strikes have been inconsistent, but at his best he looks like a mid-rotation starter. 

5. Cal Raleigh, C
Age: 24. Team: Majors

Raleigh has improved on both sides of the ball to solidify his projections as the Mariners’ catcher of the future. His receiving metrics have been the best in the Mariners organization on a nightly basis, major leaguers included, and his game-calling and leadership draw rave reviews. A switch-hitter, Raleigh has ironed out his righthanded swing to be a legitimate threat from both sides of the plate, and improved pitch recognition has helped him lay off high fastballs that previously gave him trouble.

6. Harry Ford, C/UTIL
Age: 18. Team: N/A

NEW Ford separated himself as the top prep catcher in this year’s draft class with his unique athleticism and solid hitting ability. The Mariners drafted him 12th overall, the highest a high school catcher has been taken since 2015, and signed him for $4,366,400. Ford is a plus runner who is good enough to stick behind the plate but also has the athleticism to play second base, third base or center field. He has plenty of bat speed and strength in his compact frame, with the likelihood of hitting for power over average. The track record of high school catchers is poor, but Ford has enough athleticism and hitting ability to play other positions and give him additional avenues to the majors.

7. Brandon Williamson, LHP
Age: 23. Team: Double-A Arkansas

Williamson posted 59 strikeouts and 10 walks in 31 innings at High-A Everett to earn a quick promotion to Double-A. His 91-94 mph fastball has played up with deception in his delivery and his breaking ball has become a neutralizing pitch with sharp, late break. His average changeup is improving and his control has been above-average, helping him project as a potential mid-rotation starter even though his first few starts at Arkansas have been rocky.

8. Zach DeLoach, OF
Age: 22. Team: Double-A Arkansas.

DeLoach got off to a slow start but has been on fire since May 15. He has impressed with a simple approach, sharp pitch-recognition and the ability to hit lefties as well as righties. DeLoach isn’t a particularly athletic defender and his reads and range need to improve, but his ability to hit and get on base from the left side still make him a potential everyday player.

9. Matt Brash
Age: 23. Team: High-A Everett

NEW Brash has stood out in a loaded Everett rotation and is frequently asked about by other teams in trade discussions. He was sidelined by shoulder tenderness when the Mariners acquired him from the Padres last year, but his stuff has been overwhelming since he returned. His fastball has been up to 99 mph with high spin rates, his hard, tilting slider earns plus grades and his changeup has flashed plus, although it needs further development. Brash’s command and control have been scattered, but the quality of his stuff has observers buzzing.

10. Levi Stoudt, RHP
Age: 23. Team: High-A Everett.

Stoudt was the Mariners’ third-rounder from the 2019 draft, out of Lehigh University. He had Tommy John surgery but has come through with mid-to-upper 90s velocity and a nasty, split-grip changeup which features 10 mph of separation from his fastball. His third pitch is a slider in the mid-to-upper 80s which also earns potential plus grades.

Prospects 11-30

11. Andres Muñoz, RHP

12. Juan Then, RHP

13. Edwin Arroyo, SS

NEW Arroyo was one of the best defensive high schools shortstops in the draft class and was picked by the Mariners in the second round, No. 48 overall. Still only 17 years old, Arroyo has slick hands, impressive actions and plus-plus arm strength that allows him to make any throw on the field. He has further to go offensively and was often beat by the better pitchers in the draft class, but has promise as a switch-hitter with a contact-oriented swing and room to grow into power.

14. Starlin Aguilar, 3B

15. Connor Phillips, RHP

16. Victor Labrada, OF

NEW Signed out of Cuba for $350,000 last November, Labrada made his professional debut with Low-A Modesto in mid May and electrified the club as a dynamic, high-energy presence at the top of the order. He is a twitchy, explosive defender in center field and plays hard and fast all the time, including frequently beating everyone on and off the field in between innings. While aggressive at the plate, he stays in the strike zone, makes a lot of contact with a compact, quick swing and wreaks havoc on the basepaths with plus speed. Labrada is small and lacks home run power, but he does enough to be at least a potential reserve.

17. Milkar Perez, 3B

18. Adam Macko, LHP

19. Wyatt Mills, RHP 

20. Jonatan Clase, OF  

21. Taylor Dollard, RHP

NEW The Mariners’ fifth-round pick last year, Dollard’s fastball has ticked up this season to enhance his future outlook. After sitting 88-92 mph in college, he is now ranging from 90-94 mph to help give him an average or better arsenal across the board as opposed to his stuff being a touch light. He has maintained his plus control with the increase, helping him move quickly from Low-A Modesto to High-A Everett.

22. Kaden Polcovich, UTIL

23. Alberto Rodriguez, OF

24. Darren McCaughan, RHP

NEW McCaughan continued his track record of success with elite control and below-average stuff at Triple-A Tacoma this year and made his major league debut with five no-hit innings against the Rockies on July 21. His sinking fastball ranges from 87-91 mph and none of his secondary pitches overwhelm, but effectively changes speeds to keep hitters off-balance, moves the ball around the strike zone and keeps the ball on the ground to limit damage.

25. Luis Liberato, OF

NEW Liberato got significantly stronger over the past year to give him newfound offensive thump to go with his excellent defense in center field. His power has ticked up to average and he now makes enough hard contact to potentially rise as a reserve outfielder, whereas before his bat was too light to project in any kind of significant major league role.    

26. Yohan Ramirez, RHP

27. Donnie Walton, UTIL

NEW Walton returned to the majors this season and saw time at four different positions. He remains a solid utility option for the Mariners to call upon whenever they need.

28. Cade Marlowe, OF 

NEW Marlowe has been old for his levels this year at Low-A Modesto and High-A Everett, but he’s shown enough tools for evaluators to consider him a potential future major leaguer. He has one of the best approaches in the organization, crushes mistakes with his above-average power from the left side and has shown plus speed and defense in the outfield.

29. Penn Murfee, RHP

NEW Murfee was the best starter at Double-A Arkansas and averaged more than a strikeout per inning before receiving a promotion to Triple-A Tacoma. Though older due to an unconventional path through college baseball, Murfee’s deceptive sinker-slider mix out of a low arm slot and his ability to execute a gameplan give him an avenue to the majors.

30. Gabriel Gonzalez, OF

NEW Gonzalez was signed for $1.1 million out of Venezuela in 2021 on the strength of a powerful bat, an athletic build and the ability to one day fit into the mold of a slugging corner outfielder. So far, so good for Gonzalez, who opened his career by mashing in the Dominican Summer League.


RHP Levi Stoudt has increased his fastball velocity from 91-95 mph in college to 94-98 mph this season. He’s backing it up with a power slider in the mid-to-upper 80s and a changeup that flashes at least average. Stoudt is striking out more than a batter per inning at High-A Everett with his enhanced stuff and has shown the ability to throw all three pitches for strikes, although his walk rate is still a tick too high.

OF Jonatan Clase has struggled to stay healthy since signing with the Mariners, but he’s been healthy this year and was one of the club’s top performers in extended spring training. He remains the fastest runner in the system and has worked hard in the weight room to add strength and become more of an offensive threat.


LHP Adam Macko showed swing-and-miss stuff but struggled with his control at Low-A Modesto. He was unable to avoid big innings and needs to significantly improve his control for his stuff to play consistently. 

RHP Isaiah Campbell’s stuff has declined since college, and he’s out indefinitely after having a minor elbow cleanup procedure.


RHP Logan Gilbert settled into the Mariners rotation after getting hit hard his first few starts. He posted a 2.37 ERA in his final seven starts heading into the all-star break.

OF Taylor Trammell hit .160 in 58 games and was sent down to Triple-A for the second time this season. He struggled with breaking balls and offspeed stuff in particular and struck out in more than 42% of his plate appearances. 

OF Jake Fraley worked his way into consistent playing time in the Mariners outfield and hit .237/.409/.439 with seven home runs, 23 RBIs and seven steals in 40 games through the all-star break. He mostly bounced between left and center field.

OF Sam Haggerty saw playing time at all three outfield spots and second base before going on the injured list with right shoulder inflammation in late May. He has the 12th-highest sprint speed in the majors this season but hit just .186/.247/.291 in 35 games.

1B/OF Jose Marmolejos began the year on the Mariners’ Opening Day roster but struggled to make enough contact to get to his power and was demoted to Triple-A in mid May.

LHP Anthony Misiewicz was tied for the team lead with 38 appearances out of the bullpen through the all-star break, primarily pitching in the seventh and eighth innings.

RHP Will Vest, a Rule 5 draft pick from the Tigers, posted a 6.17 ERA in 32 relief appearances before being designated for assignment on July 12.


RHP George Kirby is out with shoulder tenderness but has no structural damage. He has resumed throwing and is slated to return to games within the next two weeks. 

LHP Adam Macko missed five weeks with shoulder tenderness but returned in mid July.

RHP Isaiah Campbell had a minor cleanup procedure on his elbow but has no set timetable to return. 

RHP Andres Muñoz is on schedule in his rehab from Tommy John surgery. He is unlikely to return this season but should be ready for the start of next season.

RHP Joey Gerber is dealing with unspecified back issues and is not close to returning to the mound. He has no specific timetable.

RHP Ljay Newsome has been out since May 8 with right elbow inflammation and is on the 60-day injured list.

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