The Mariners are calling outfield prospect Lazaro Montes up for his MLB debut, according to reporter Francys Romero. Montes will join the team on Tuesday in Boston when rosters expand to 28 players, as per Ryan Divish of the Seattle Times, plus another transaction will need to be made to create space for Montes on the 40-man roster.
An international signing for the M’s in January 2022, Montes has steadily mashed his way up the minor league ladder, with increasingly impressive power numbers. Montes hit .234/.369/.550 with 25 homers over 339 plate appearances with Double-A Arkansas this season and earned himself a Triple-A promotion in July, then kept the big hits coming with 13 home runs and a .267/.359/.564 slash line in 198 PA for Tacoma.
At 6’5″ and 210 pounds at age 21, Montes profiles as a classic slugger who isn’t quite a three-true-outcomes type. He has a 30.7% strikeout rate across both minor league levels in 2026, so while big league pitchers are likely to find holes in Montes’ swing, the Mariners are hoping Montes can do plenty of damage when he does make contact.
MLB Pipeline ranks Montes as the 56th-best prospect in the game, and Baseball America is right behind with a #58 ranking in its most recent midseason top-100 update. Evaluators praise Montes’ approach at the plate and also give his throwing arm a 60-grade, lending credence to the idea that Montes can stick as a right fielder. While a DH role is probably in Montes’ future, his arm gives him some defensive value even if his fielding is overall subpar.
It’s safe to guess that the Mariners couldn’t care less about Montes’ glovework at this point, as the club is badly in need of some offensive help. Seattle ranks in the middle of the pack in home runs, but rank dead last in the league in runs (540) and near the bottom in slugging percentage (.372), on-base percentage (.307), and average (.227). The lack of offense is the biggest reason why the M’s are 64-73, and five games behind in both the AL West and wild card races.
While it’s unfair to expect a rookie to suddenly turn a season around, the Mariners have nothing to lose in seeing if Montes getting some at-bats at DH or in right field. Taylor Ward‘s offense has cratered since being acquired from the Orioles at the trade deadline, so since regular DH Dominic Canzone has been hitting well, Ward is the likelier candidate to lose playing time once Montes joins the roster.
Montes will retain his rookie eligibility into 2027, as he won’t amass the minimum 130 plate appearances or 45 days on an active roster. This leaves him eligible for the Prospect Promotion Incentive and the Mariners eligible for an extra pick in the 2028, assuming the PPI system isn’t altered in the next Collective Bargaining Agreement.
As to what other player could be joining the M’s on September 1, MLB.com’s Daniel Kramer writes that Michael Arroyo won’t be called up to join Montes or Kade Anderson as top prospects now on the Seattle roster. The Mariners may not make their next decision on a 28th man until Tuesday, when they’ll have more time to access Brendan Donovan‘s recovery from a concussion.