MLB international signing period: what to know

The Mariner's amateur scouting team prepares to show their chops again in the Caribbean, Central and South America.

Seattle Mariners v Detroit Tigers
Seattle Mariners v Detroit Tigers / Mark Cunningham/GettyImages

Felnin Celesten, Lazaro Montes, Michael Arroyo, and even the great Julio Rodriguez all have one thing in common: the Mariners signed each through the international signing process. This year, the annual event kicks off on January 15 and lasts through December 15, with teams signing eligible players (at least 16 years old on signing day) to multi-year contracts. Players from this year's class must have birthdates between September 1, 2006, and August 31, 2007.

The interesting thing about the international signing period is the rules behind bonus pools. The Mariners currently have $6,520,000 to spend this period. Like the Major League Baseball draft, teams can go over the slot (based on the 2023 Top 50 list) to lure players away from other teams. We've seen the Mariners take this approach with last year's signees Celesten and righty starter Jeter Martinez. That's where the similarities between the ISP and the MLB Draft end.

The international signing period is nearly a year-long effort, which means the list of new Mariners will evolve as we work through the calendar. Baseball America has linked the Mariners to two shortstops, Dawel Joseph (4) and Leandro Romero (48).

Scouts rave about Joseph's upside as an authentic speed and power threat from a premium position—every tool grades above average with the hit, run, and fielding carrying the 16-year-old right now. His simple and direct path to the ball is paying dividends, as well as an increased walk rate and in-game power. Comparisons have ranged from Francisco Lindor to Bryon Buxton, which is a lot of pressure to put on a young kid.

Romero is a solid middle infielder with more of a gap-to-gap approach in the box and a still-developing defensive game. All reports suggest the Mariners are taking a flyer on him due to his tremendous upside. The swing will need work, and Romero will likely settle at second base or as a super-utility man due to the quality depth of shortstops already in the system (Celesten, Cole Young, Tai Peete).

Exciting times are on the horizon for an already spectacularly deep Mariner's farm system. Stay tuned for updates on the upcoming international signing period and any rumored signings.