Top 50 graphic design by Michael Packard, @CollectingPack on Twitter
Seattle Mariners
AL West
2025 record: 90-72 (1st)
MiLB affiliatesIndianapolis Indians
Triple-A: Tacoma Rainers
Double-A: Arkansas Travelers
High-A: Everett AquaSox
Single-A: Inland Empire 66ers
2025 End-Of-Season farm system rank: #4
Jeremy Mahy’s organization take from our 2025 End-Of-Season Farm System Rankings:
The good news. The Mariners have players on MLB Pipeline’s Top 100 list. The bad news. There is a decent drop off from there. The Mariners have a young and talented major league roster, especially on the pitching side. At the top of their farm system sits another wave of talent ready to contribute to their next playoff run. Their window looks to be wide open with no sign of closing anytime soon.
2026 International Signings: Juan Rijo, OF, Dominican Republic ($2.2 million)
and Gregory Pio, OF, Dominican Republic ($2.9 million). The two aren’t included in this new Top 50, but they’d likely be slotted in Tier 5. Both should be in our next Mariners update when that comes out later in the year.
Prospects1500 writers who contributed to this column and rankings: Greg Bracken (@gregbracken07), Scott Greene (@Scotty_Ballgame), Shaun Kernahan (@ShaunKernahan), J.W. Mulpas (@CLEBoxscoreBeat), and Jeremy Mahy (@JMahyfam). The writer’s Twitter handle follows each player write-up or paragraph.
Prospects1500 Tiers:
Tier 1: Players with high expectations of both making the majors and playing at an All-Star level for a number of years
Tier 2: Players with an above-average expectation of making the majors and being a solid contributor
Tier 3: Players with an average expectation of making the majors and being a solid contributor
Tier 4: Players who have the potential to make the majors; possible sleeper candidates for sustained MLB success
Tier 5: Players of interest, worth keeping an eye on, who may make (or have made) the majors but provide minimal impact
Levels listed for each player are the highest levels player reached in 2025
Tier 1
1. Colt Emerson, SS, 20, Triple-A
Emerson has the highest probability of being an everyday contributor at the big league level as anyone in this system. His exceptional bat-to-ball skills and plate discipline give him one of the highest floors in the all the minors, and his ability to consistently post strong on-base percentages should be enough to keep his bat in a major league lineup. While he showed more power in 2025, his swing path is not geared for loft which could limit his over the fence power. Twenty home run pop is not out of the question with him and it will likely come plenty of doubles. (@JMahyfam)
2. Kade Anderson, LHP, 21, College
Anderson is a polished four-pitch left-hander whose blend of command, feel, and pitchability gives him one of the more advanced starter profiles in the Mariners system. He sits 92–95 and reaches 97 with quality life and carry, holding velocity deep into outings while confidently attacking the zone. The changeup has developed into a true plus offering he can deploy in any count, and he complements it with a sharp mid-80s slider that flashes plus with two-plane depth, along with a high-spin curveball that plays above its grade thanks to shape and tunneling. He shows the ability to manipulate his mix depending on the matchup, working from different rubber positions and maintaining pace and athleticism throughout his delivery. With four legitimate weapons, strike-throwing ability, and the durability to handle starter workloads, Anderson projects as a high-floor mid-rotation arm with the upside to pitch near the front of a rotation if the secondaries continue to sharpen. (@ShaunKernahan)
Tier 2
3. Ryan Sloan, RHP, 20, High-A
The Mariners went well over slot value to lock down Sloan in the second round of the 2024 Draft and so far, that investment looks warranted. In 82 A-ball innings last year the 19-year-old posted a 27% strikeout rate while only walking 15 hitters all season, impressive control and command for such a young kid. His arsenal is headlined by a fastball that sits 97–98 mph and has touched triple digits. His changeup plays well off his fastball with late tumble that has kept hitters off balance. His slider shows promise and if it continues to develop, he could have frontline potential. As with all young hard throwing pitchers that touch triple digits, durability will be a concern but so far the Mariners are being cautious with the young hurler. (@JMahyfam)
4. Lazaro Montes, OF, 21, Double-A
Montes’s profile is built around his massive raw power, the kind of power that could translate into 30 or more home runs annually. The physically imposing corner outfielder has produced elite exit velocities but is working to rein in his aggressiveness at the plate. As he has faced better pitching that aggressiveness has proved to be a hurdle, striking out 28% in High-A and 30% in Double-A. He just turned 21 years old in the offseason and is walking at a respectable rate as well, allowing him to post a .385 wOBA last season. If the hit tool stabilizes, he has All-Star potential. Just be patient as he irons out his swing decisions and ability to recognize spin. (@JMahyfam)
5. Jonny Farmelo, OF, 21, High-A
Thanks to Julio Rodríguez winning the Rookie of the Year in 2022, the Mariners were able to select Farmelo with their compensation pick the following year. A tooled up outfielder with excellent speed and significant bat speed, he projects as a player with both top-of-the-order skills and the potential for future power. However, his development has been slowed by injuries the past two seasons. When healthy, Farmelo has shown the kind of athleticism and offensive traits that could make a dynamic leadoff hitter with a solid batting average. Think 30 plus stolen bases with 10-12 home runs. (@JMahyfam)
6. Michael Arroyo, 2B, 21, Double-A
Arroyo’s offensive profile is built on his ability to control the strike zone and post high on-base percentages giving him a strong offensive foundation. He began last season in HighA, and after starting slowly, he found his rhythm in May, earning him a promotion to DoubleA in June, where he finished the year with a combined .262/.401/.433 slash line with 17 home runs and 12 stolen bases. While he may not offer elite speed, his developing power and strong plate discipline should make him a steady fantasy asset. In a system chalked full of high-level talent don’t sleep on Arroyo. (@JMahyfam)
Tier 3
7. Felnin Celesten, SS, 20, High-A
8. Luke Stevenson, C, 21, Single-A
9. Nick Becker, SS, 19, Single-A
10. Yorger Bautista, OF, 18, Rookie (DSL)
Celesten is an athletic, switch-hitting shortstop with plus defense and big upside. Despite a dip in contact and an uptick in strikeouts in 2025, he remains a high-ceiling prospect who’ll look to rebound in 2026. Stevenson is a powerful, disciplined hitter who impressed in his pro debut at Single-A and benefits from Cal Raleigh’s mentorship behind the plate. Becker is a projectable, athletic shortstop with advanced pitch recognition and plus speed, but he’ll need to develop more power to reach his potential. Bautista, nicknamed “La Bestia,” has impressive power and is a breakout candidate this season if he can improve his contact rate. (@CLEBoxscoreBeat)
Tier 4
11. Korbyn Dickerson, OF, 22, Single-A
12. Teddy McGraw, RHP, 24, High-A
13. Griffin Hugus, RHP, 22, College
14. Michael Morales, RHP, 23, Double-A
15. Luis Suisbel, 3B, 22, High-A
16. Christian Little, RHP, 22, High-A
Dickerson, last year’s 5th round pick out of Indiana, had a 2-game debut with Single-A Modesto. Give him some time back in A (Inland Empire now) or potentially look for the outfielder to be assigned to Everett to start 2026. McGraw, who’s already had TJS twice, had a solid season, posting a 3.14 ERA in 14 games (12 started) across the Complex League and High-A. Hugus, Seattle’s 3rd round pick out of Miami, by way of Cincinati, will debut this season. The 6’2″, 195 lb righthander is probably ticketed for Inland Empire’s rotation along with Anderson. Morales doesn’t strikeout a lot of batters (only 6.2 K/9 last season, down from 8.9 in 2024), but he’d had some success at Double-A and may get some more time in Arkansas this year in hopes of seeing Tacoma at some point during the second half. Suisbel was a pop-up prospect in 2023 after hitting .291, and he’s hit 15 HR (2024) and 23 HR (2025) since. Look for him to impress in Double-A this season, and my bold prediction is he’s a Top 100 prospect by the end of 2026. Little made 17 starts (2 at High-A) last season, and should be back in Everett to start 2026, in the same rotation with Slaon and McGraw, which should be a fun team to watch. (@Scotty_Ballgame)
Tier 5
17. Marcelo Perez, RHP, 26, Double-A
18. Brock Rodden, SS/2B, 25, Double-A
19. Jared Sundstrom, OF, 24, Double-A
20. Mason Peters, LHP, 22, College
21. Carlos Jimenez, OF, 23, Single-A
22. Rhylan Thomas, OF, 25, MLB
23. Leandro Romero, SS, 19, Rookie (DSL)
24. Victor Labrada, OF, 26, Triple-A
25. Blas Castaño, RHP, 27, MLB
26. Robinson Ortiz, LHP, 26, Triple-A
27. Dawel Joseph, 3B/SS, 18, Rookie (DSL)
28. Josh Caron, C, 22, High-A
29. Grant Knipp, C/RHP, 24, Injured (College in 2024)
30. Tyler Cleveland, RHP, 26, Double-A
31. Charlie Pagliarini, 2B, 25, High-A
32. Chia-Shi Shen, RHP, 22, Single-A
33. Charlie Beilenson, RHP, 26, Double-A
34. Kendry Martínez, 2B/SS, 18, Rookie (DSL)
35. Lucas Kelly, RHP, 22, High-A
36. Grant Jay, C/OF, 22, College
37. Po-Chun Lin, RHP, 19, Injured (International signee in 2025)
38. Aiden Taurek, OF, 22, Single-A
39. Brennen Davis, OF, 26, Triple-A
40. Elias Perez, OF, 18, Rookie (DSL)
41. Walter Ford, RHP, 21, Single-A
42. Peyton Alford, LHP, 28, Double-A
43. Juan Cazarez, RHP, 20, Rookie (ACL)
44. Taylor Dollard, RHP, 27, High-A
45. Manuel Almeida, C, 18, Rookie (DSL)
46. Jimmy Joyce, RHP, 27, Double-A
47. Sebastian De Andrade, C, 19, Rookie (ACL)
48. Diego Contreras, 2B/3B, 18, Rookie (DSL)
49. Ricardo Cova, OF, 21, Single-A
50. Dervy Ventura, 2B, 22, Single-A
Perez continues to provide steady innings at Double-A Arkansas, and while the 26-year-old may profile more as upper-minors depth, a strong first half could put Tacoma in play. Rodden’s versatility up the middle keeps him relevant, though the bat will need to show more impact if he’s going to push beyond Arkansas. Sundstrom has shown some pop in spurts, but consistency at the plate will determine whether he factors into Seattle’s outfield depth picture. Peters, the 22-year-old lefty out of college, should make his pro debut in 2026 and could move quickly if the polish matches the scouting reports. Thomas already has MLB time under his belt and looks like a viable fourth-outfielder option who can shuttle between Seattle and Tacoma as needed. Labrada brings speed and defensive value in Triple-A, but the on-base skills will have to tick up to carve out more than a reserve role. Castaño has logged big league innings and fits as bullpen depth who can be called upon when the need arises. The Mariners are hoping 18-year-old Joseph’s bat develops as he fills out physically. Shen handled Single-A well for his age and could see Everett if the strike-throwing continues to progress, while Lin is rehabbing and remains more projection than production for now. Taurek showed flashes of athleticism in A-ball and will need a more consistent offensive approach to climb a tier. Davis is looking to reestablish himself after bouncing around in recent years, and a productive run in Tacoma could at least put him back on the radar. Dollard is working his way back through High-A as he rebuilds value, and Joyce offers experienced relief depth at Double-A with a chance to see Tacoma if the strikeouts hold. (@Scotty_Ballgame)
Author
Prospects1500 is your comprehensive dynasty league resource, featuring deep MLB/MiLB top prospect lists, news and rankings.
President of Prospects1500. Founder of Diamond Duos dynasty fantasy baseball leagues and the MLB Fantasy Playoffs Parlay. Participant and champion in several dynasty/fantasy baseball and football leagues. Sales Manager for Reminder Publishing by day. Huge Bruce Springsteen and pro wrestling fan. Along with his wife and two boys, lives in Longmeadow, MA. Follow on Twitter at @Scotty_Ballgame.
Jeremy covers the St Louis organization and contributes on Prospects of the Week for Prospects1500. Born and raised in the Midwest, he is a lifelong fan of the Birds on the Bat. You can follow him on Twitter @JMahyfam for more baseball content.
“Love is the most important thing in the world, but baseball is pretty good, too.” -Yogi Berra
Shaun Kernahan is the MLB Draft correspondent for Prospects1500. When not at a game, chances are the TV and/or tablet has a game on and he has a notepad out taking notes. When not scouting draft prospects, he is the Director of Baseball Operations for the Mile High Collegiate Baseball League, a collegiate wood bat league in Colorado. Shaun can be found on Twitter at @ShaunKernahan.
Greg covers the Toronto Blue Jays organization for Prospects1500. Born and raised in Toronto, Ontario, a long-suffering fan of both the Blue Jays and the Toronto Maple Leafs. For more than 15 years now a participant/commish in many dynasty baseball leagues, all with extremely deep minor league rosters. Follow on X @gregbracken07.
J.W. resides in Northeast Ohio and is a lifelong Cleveland sports fan. His favorite baseball player of all-time is 2018 Hall of Fame inductee, Jim Thome. He enjoys playing Fantasy Baseball, especially dynasty leagues. He has been a contributor to Prospects1500 since January 2025. You can follow J.W. on X at @CLEBoxscoreBeat.