3 surprises in MLB Pipeline's top 30 Mariners prospects for 2025

Despite being one of the more passive teams this offseason and doing little to improve the roster at the big-league level, the Seattle Mariners' farm system is poised to remain one of the best in the business.

With the start of the minor league season just around the corner, MLB Pipeline recently updated their list of top 30 prospects for each organization. While the Mariners' top names have more or less maintained their spots from the previous year, that can't be said for everyone.

Here are the three biggest surprises to come out of MLB Pipeline's 2025 rankings for the Mariners' top prospects.

Surprise No. 1: Tyler Locklear

For the 2024 season, MLB Pipeline ranked Locklear as the Mariners' No. 6 prospect and praised his power at the plate. He split time between Double-A Arkansas and Triple-A Tacoma in the minors last year, struggling to adapt his approach with the increase in competition. He had a 160 wRC+ over 188 plate appearances in Double-A but just a 103 wRC+ over 318 plate appearances in Triple-A.

Locklear also made his major league debut to disappointing results, slashing just .156/.224/.311 over the 16 games he played. His subpar numbers at the higher levels of baseball coupled with the relative success of other players in the farm system have caused him to slip down to the No. 11 spot on the Mariners' prospect list for 2025.

The 24-year-old still has the potential to be an impactful presence in the lineup. His raw power is still there and his 2024 struggles should not obscure that he took a major step up after spending the majority of 2023 with High-A. Given a full year at Triple-A and the lingering uncertainty at his primary position, there's a chance for him to be a real contributor in 2025.

Surprise No. 2: Michael Arroyo

Since signing as an international free agent in 2022, Arroyo has been a well-respected prospect. He was ranked by MLB Pipeline as the No. 41 prospect among his class and he had solid numbers in his first full minor-league season in 2023, posting a 118 wRC+ over 265 plate appearances in Single-A Modesto.

Scouts reported that what he lacked in natural power was made up for by an above-average ability to find his barrel and get the most out of his swing. He was the Mariners' No. 12 prospect in 2024, yet was seen as a tier below fellow middle infielders Cole Young and Colt Emerson.

However, Arroyo took a massive step forward offensively last year, splitting time between Single-A Modesto and High-A Everett and posting a 148 wRC+ over 592 plate appearances. He hit 26 doubles, seven triples, and 23 homers, crushing his numbers from 2023 where he managed just 17 doubles and three homers. This helped him move up to the No. 7 slot, right below outfielder Jonny Farmelo and above Ryan Sloan. More importantly, he cracked MLB Pipeline's overall top 100 at the No. 97 spot.

Fans should get a chance to see whether Arroyo's stuff will hold up in the higher levels of the minors. In the meantime, he has been getting some spring training at-bats while also helping the Colombian national team qualify for the 2026 World Baseball Classic.

Surprise No. 3: Jurrangelo Cijntje

To many, Cijntje was the most intriguing selection in last year's draft simply because of his status as an ambidextrous pitcher, something that hasn't been seen since Pat Venditte's unique skillset forced MLB to implement a rule change. It was also the organization's first college pitcher selection in the first round since Emerson Hancock was drafted in 2020.

While many speculated that Seattle would simply make Cijntje focus on one arm, it seems that the Mariners are giving him a chance to use both for now. The issue that scouts have reported is that as a righty, he resembles more of a starter, using a fastball in the high-90s with an effective slider and a great changeup. As a lefty, he loses significant velocity and has just two pitches. His arm slot also seems lower as a southpaw, likely the cause for the disparity in power.

Combined with his frame being on the slightly smaller side (5-foot-11, 200 pounds) and there already quite a few obstacles to him being a viable arm in the rotation at the big-league level.

Despite being the organization's first pick last year, Cijntje is now ranked one spot below Sloan, a fellow 2024 draftee chosen 55th in the second round. He'll get his first taste of professional baseball in 2025 and if his numbers as a true switch pitcher are good, he could rise the prospect ranks quickly. He's already hard at work refining his gifts, so it might not be long before he exceeds current expectations.