3 Mariners trades that could finally pay off in a big way in 2025

The Seattle Mariners are not known to be a recurring contender in top free agent discussions, but they've remained pretty active on the trade front over the past few years.

It may have been difficult to tell because some acquisitions have been dealing with injuries, while others simply haven't played a full year in a Mariners uniform yet. All the same, here are three guys who could emerge as major contributors in 2025.

2B Ryan Bliss

Ryan Bliss was one of three players the Arizona Diamondbacks sent to Seattle in 2023 in exchange for Paul Sewald, who helped them in a playoff push that culminated in a World Series appearance.

Per MLB Pipeline, Bliss had been Arizona's No. 16 prospect in 2022 before falling out of the top 30 for 2023 after a rough season with High-A Hillsboro. He bounced back in a big way that year, posting a 127 wRC+ while splitting time between Double-A and Triple-A.

He continued his success in 2024, posting a 110 wRC+ with 54 stolen bases across 433 plate appearances in Triple-A Tacoma and finally making his big league debut, finishing with a 102 OPS+ over 71 plate appearances for the Mariners.

Bliss has been working his way up the depth chart at second base and continues to make a strong case for himself in spring training. He's a dynamic prospect with lots to offer. And with the keystone up for grabs in Seattle, he could be setting himself up for a breakout year.

RHP Gregory Santos

It hasn't been an easy time for Gregory Santos since he arrived in Seattle via a February 2024 trade with the Chicago White Sox.

Around this time last year, he suffered a lat strain, sidelining him for Opening Day and starting a chain of injuries that limited him to just 7.1 innings in 2024. Now, he's reportedly back to full health and has been great in spring training, tossing 4.2 innings to a 1.93 ERA.

We can make guesses on what a healthy Santos will do for this bullpen based on what he did in his lone full season at the major league level. In 2023, his chase rate (33.5 percent), whiff rate (30.0), walk rate (5.9), and hard-hit rate (34.8) were in the top quartile of qualified pitchers, while his barrel rate of 1.5 percent was the lowest of any MLB pitcher with more than 100 batters faced.

Santos used an unorthodox pairing of power and inducing soft contact to get his outs. With another year of development in an organization as proficient in developing pitching as the Mariners, it wouldn't be surprising to see him be even better than he was with the White Sox.

LF Randy Arozarena

Along with Justin Turner, Randy Arozarena was one of the offensive reinforcements brought in by the front office for a desperate playoff push last year. Things didn't quite work out for the team, and Turner was only in Seattle for the duration of his one-year contract. However, Seattle will have team control over Arozarena until he becomes a free agent after 2026.

Arozarena had some struggles in the first half of last season with the Tampa Bay Rays, but dialed it in with the Mariners, accumulating 1.0 rWAR in just 239 plate appearances. He ultimately notched his fourth straight 20-20 season, and his OPS+ for the Mariners (118) from last season is in line with that fans can expect in 2025.

He's not perfect and despite his penchant for eye-catching work in the outfield, his defense is quite bad across the board. However, along with Julio Rodríguez and Victor Robles, he's part of what is shaping up to be an exciting trio in the Seattle outfield.