This Mariners player could be prospect of the future or offseason trade bait

It was nothing short of a fantastic 2024 season for Seattle Mariners prospect, Michael Arroyo. The Cartagena, Colombia native is still just 19 years old and wrapped up his third professional season. The club signed him for $1.375 million back in 2022 as a 17-year-old, and he's hit the ground running ever since.

Arroyo debuted in 2024 with Low-A Modesto. That's where he left off in 2023, and by midseason he was on his way north to High-A Everett. With Modesto, Arroyo slashed .279/.404/.500 with 11 doubles, five triples, and 11 home runs in 60 games. Many of those metrics only improved following Arroyo's midseason promotion.

For the Aqua Sox, he finished the year with a 155 wRC+, a .228 ISO, and a .290 average — all career-best marks for Arroyo with a full-season affiliate. The young second baseman ranks 12th on the team's Top 30 prospect list, according to MLB Pipeline. Baseball America even ranks Arroyo in their Top 100 prospects, at No. 96 overall. It's been a quick rise, but the potential of missing the postseason — alongside the team's offensive struggles for much of the season — begs the question: is Arroyo part of the Mariners' future or should he be trade bait this offseason to improve the big league roster?

Arroyo's excellent production despite his relative youth is highly intriguing

Without question, the Mariners need more offense in the coming years. The team will need to build a core around current superstar Julio Rodriguez. That can't all come via free agency. Key prospects such as Colt Emerson, Cole Young, Lazaro Montes, and Arroyo could very well represent a good portion of the eventual build-out. Among qualified prospects in the Seattle farm system this season, Arroyo ranked better than anyone with a 146 wRC+. That elite production and his youth make the future potentially very bright. Arroyo is younger than Young, Montes, and Harry Ford.

It could be just what Seattle needs. The team hasn't had such a high-profile second base prospect since perhaps Dustin Ackley. With Young at shortstop, Colt Emerson at third base, and Arroyo manning second base, the Mariners could very well have their infield of the future all in the farm system right now. Each player ranks somewhere on various Top-100 prospect lists out there. So what's the timeline? That's where questions may start to crop up around Arroyo's future with Seattle.

Michael Arroyo's timeline may not be as quick as the team needs at this point

Despite firing Manager Scott Servais earlier this season, the Mariners' contention window remains wide open. Superstars Julio Rodriguez and Randy Arozarena are in town for the foreseeable future. Then, of course, there's the starting rotation. The team's rotation is the clear strength of the Major League roster. Unfortunately, with free agency looming for a couple of key starters, that may not be the case for more than a few more seasons.

Logan Gilbert has three years remaining on his contract following the 2024 season. All three years will fall under arbitration. Fellow Super Two-eligible starter George Kirby will enter that first year of arbitration next season. His potential free agency looms a year beyond Gilbert, who is set to hit the open market in 2027. Luis Castillo's six-figure contract runs until 2027 but includes a mutual option for the 2028 season. All of that comes together into a lot of rotation question marks for 2027 and beyond. By the time players such as Montes and Arroyo are ready for the big leagues, the Mariners' rotation likely looks vastly different than today. The team is certainly in a "win-now" window, and prospects such as Arroyo don't contribute to that yet.

Questions around approach and defense sow doubt around Arroyo's big league future

The need to win now isn't the only reason to consider trade offers for Arroyo. The Mariners could still make moves to prioritize their championship window without sacrificing key elements of the team's future. However, with Arroyo, there are other concerns worth mentioning.

First and foremost, Arroyo is a young prospect. Many of the opportunities he has now are normal for young players. Among those is his approach at the plate. At a September game we were present for this year, he saw just nine pitches in the game. Four of those came on a strikeout in his final appearance of the game. There's still time for the organization to develop a better approach at the plate. It's obviously working more often than not — for now. Arroyo's results at the plate are fantastic currently, but there's little question that he will need to look for better pitches and find more patience by the time he's ready to move up to Double-A and beyond.

More concerning than approach are Arroyo's lacking fundamentals and defensive skills. If he ends up in the infield, it certainly won't be on the left side. Arroyo lacks range to play at shortstop and his arm is far too below-average to be effective at shortstop or third base. That forces Arroyo to second base where his defense remains very poor. Routinely, he makes errant throws that turn into errors. In 14 games at shortstop this season, he committed five errors. At second base, he committed 21 in 94 games. It's simply atrocious. There's no better way to put it.

Fundamentally, it isn't always pretty either. Arroyo stole 10 bags for the Aqua Sox in 2024, but was caught five other times. In the September game we attended, he was very poorly picked off between first and second immediately after getting on base via hit by pitch. Those defensive miscues and mental mistakes will have to improve for Arroyo to offer enough value to play defensively at the next level.

Considering the total package, trading Arroyo now makes a lot of sense for the Mariners

Putting everything together, the Mariners should absolutely entertain trades that include Arroyo this offseason. It's doubtful his future value is so low that the team has to force a deal. However, it seems entirely possible that his current value as a prospect is the peak of what it ever will be. The organization already traded one teenager in A-ball in Edwin Arroyo two seasons ago. That trade has certainly worked out for Seattle. Luis Castillo has been worth 5.7 fWAR with the Mariners and Edwin missed all of 2024 with a shoulder injury.

Prospects are just that. They're potential for the future, and for the Mariners, the future should be now. The team doesn't need to mortgage the future to win next season. Colt Emerson should be untouchable at this point. Cole Young is close enough to the big leagues that he belongs in that group as well, along with shortstop Felnin Celesten and 2024 first-rounder Jurrangelo Cijntje.

Beyond those four, the Mariners should absolutely be willing to deal from a fairly deep farm system in order to surround the rotation and Julio Rodriguez with more talent to maximize this window.