Lookout Landing’s 2025 Prospect Rankings: #4 Michael Arroyo

Let me see you hit like you come from Colombia.

My favorite prospect in the Seattle Mariners system is this brawny youngster from Cartagena, Colombia. I liked Michael Arroyo immensely since signing, as there’s a compelling projection to me in prospects with experience and performance at the national level for their country. The compact infielder was already a top-notch performer for the Colombian youth team before signing with Seattle for the largest bonus inked by any player in the history of his country. Those expectations haven’t crushed the 20 year old; in fact, to the contrary. He enters 2025 on the heels of a star turn in World Baseball Classic qualifiers for his country, and having starred at the Low-A Modesto and High-A Everett levels as a teenager in 2024.

Arroyo executes this with a tidy swing that he replicates well, modulating to the point of contact and adjusting to off-speed better than most of his contemporaries, and better than many big leaguers to boot. With a short-levered swing, he can cover the inner and outer halves of the plate equally well.

Arroyo is a hit machine who’s shown no sign of slowing down in either power or contact as he’s been exposed to higher and higher levels of competition. The reason he comes in at #4 on our rankings, despite his compelling track record, is lingering questions about his defensive home. Signed as a shortstop, currently a crowded position in the Mariners’ system, the Mariners moved Arroyo to second, where his powerful bat will play. His defense, however, has been inconsistent, specifically his throws.

This spring, Arroyo took part in a special pre-spring training defensive camp run by Perry Hill, who has a specific list of things he wants to see Arroyo improve, starting with his throwing motion. Hill wants to see Arroyo consistently get the ball out of the glove quickly with the proper motion, getting his glove hand into position (thumb pointing down), balancing his elbows, and throwing from a straightened-up, not pitching forward, position while starting his throws.

Arroyo’s speed and quick reflexes help him get to balls quickly, but he can spoil the beginning of an excellent play by making a poor throw. The first baseman cleans this throw up, but you can see how he’s bent over while beginning his throwing motion, which results in an off-target throw.

For his part, Arroyo has been a dutiful student of Hill’s teachings. Hill—or “Hueso,” Spanish for “Bone”—is well-known even to the young international players, who know his reputation for being a Gold Glove factory. However, Arroyo’s time with Hill this spring was interrupted by his star turn with Team Colombia, and soon he will pack up and head off to Everett or Arkansas, away from Hill’s watchful—and more critical than paternal—eye. It will be up to him to internalize “Hueso’s” teachings and continue to improve his defense, the last step he needs to start cracking those Top-100 lists.