5 Prospects the Seattle Mariners should seriously consider trading at the deadline

With the Seattle Mariners looking more and more like buyers at the trade deadline, the team will have to make some difficult choices about which prospects they keep and which they ship out.

With eight top-100 prospects, the Mariners have an embarrassment of riches in their farm system. Here are five prospects the team should seriously consider trading, given its needs at the MLB level.

Note: All ranks are according to MLB Pipeline.

The Mariners need to seriously consider moving these 5 prospects

1. Michael Arroyo, INF: No. 61 overall prospect, Mariners No. 5

Arroyo would be tough for the Mariners to lose, but if the team wants to improve, this might be the best way to do it without losing an untouchable prospect such as Colt Emerson or Lazaro Montes.

Arroyo is slashing a ridiculous .313/.427/.537 in Double-A Arkansas. That's enough to catch anyone's eye, especially in such a pitcher-friendly ballpark. Arroyo is not the Mariners' highest-rated infield prospect, which makes him expendable. If the team would rather keep him, it could be shortstop prospect Felnin Celestin on the way out instead.

2. Jurrangelo Cijntje, SP: No. 75 overall prospect, Mariners No. 7

Cijntje possesses one of the most unique tools in the league in that he's a switch-pitcher. It's a cool trait that's helped him generate a lot of hype in prospect circles. It even earned him an appearance in the MLB Futures Game. He's also a former first-round pick who feels like a sure bet to eventually perform in the big leagues.

What makes him a potential trade chip is that it feels like Cijntje is more hyped up than the numbers suggest he should be, particularly when looking at his lefty-righty splits. Cijntje has been much better as a right-handed pitcher and has struggled with control from the left side. He's walked the same number of batters from each arm, despite throwing right-handed around three-quarters of at-bats.

3. Jeter Martinez, SP: Mariners No. 14 prospect

Martinez showed flashes of brilliance in rookie leagues, with a 1.72 ERA in 2023 and a 3.86 ERA in 2024.

Single-A Modesto has been more challenging for the young pitcher. He has a 6.71 ERA in 15 starts over 57.2 innings. His walk rate is up, his strikeout rate is down and his WHIP is a career-worst 1.70. Martinez certainly still has tools, but the Mariners might be wise to trade him before he loses any more value.

4. Teddy McGraw, SP: Mariners No. 15 prospect

The Mariners have been taking things very slow with their No. 15 prospect. McGraw was the team's third-round pick in 2023, but did not make his pro debut until 2024. Since then, he has thrown a grand total of 27.1 innings between three teams in the Mariners' minor-league system.

He's been solid overall with a 3.29 ERA and 1.43 WHIP, but it feels like between his injuries (he's had Tommy John surgery twice already) and his lack of progression, he is probably destined for the bullpen. That should make him expendable as a trade asset.

5. Jared Sundstrom, OF: Mariners No. 23

With legitimate five-tool potential, Sundstrom feels a little underrated in a loaded Mariners system. He'd probably be well within the Top-20 in most other farms, but in Seattle, he falls to No. 23.

He is 24 and has been playing well in Double-A Arkansas, indicating that he should be big league ready soon. Teams looking for the next Dominic Canzone might be interested. In Double-A, he's posted a .726 OPS with 14 doubles, eight home runs and 25 stolen bases in 72 games.