Mariners calling up big-time slugger Montes (source)

TORONTO -- The Mariners are adding a big bat and an even bigger personality to their roster for the stretch run, as outfielder Lazaro Montes is expected to join the club this week in Boston, sources told MLB.com on Sunday night.

Montes, the Mariners’ No. 5-ranked prospect and MLB Pipeline’s No. 56 overall, won’t be officially added until Tuesday, when rosters across the league expand from 26 to 28 players.

And the 21-year-old is expected to get regular at-bats, and -- the club hopes -- provide a jolt to a lineup that was held to just one hit in Sunday’s 7-0 loss to the Blue Jays.

Michael Arroyo (SEA No. 3 / MLB No. 45), who is good friends with Montes and looked like a strong candidate to be called up, is not expected to be at this time, a source said.

Montes will need to be added to the Mariners’ 40-man roster ahead of Tuesday’s game against the Red Sox at Fenway Park, which is currently at capacity.

And he would’ve been anyway this winter, as this will be his first offseason in which he’d be eligible for the Rule 5 Draft. So, too, is Arroyo.

Seattle will also be able to add another pitcher when rosters expand, and it’s also possible that more moves among its position players could come as well. The latter hinges on the status of Brendan Donovan, who continues to experience concussion symptoms but has been recovering with the team on its road trip.

Montes is a native of Cuba who joined Seattle for $2.5 million in the 2022 international signing class. And the club hasn’t had a prospect possessing this kind of power potential in the Jerry Dipoto era, other than maybe Julio Rodríguez. Just as much, it's his infectious personality that's resonated so greatly among teammates and Mariners fans.

Standing every bit 6-foot-5 and 210 pounds, Montes has swatted a career-high 38 homers this season that rank second in all of Minor League Baseball. Over his five seasons in pro ball, he’s got 114 homers and a .527 slugging percentage.

That includes 13 at Triple-A Tacoma, where he was promoted to on July 7, and where he’s slashed .267/.359/.564 (.923 OPS) in 172 plate appearances across 43 games. He’s played 40 of those contests in right field.

And where he fits positionally will be the more curious development as he reaches The Show.

The biggest question mark in Montes’ development is how his glove will play as he ascends in his player development. Many scouts have suggested that he’ll be a designated hitter longer term. However, Mariners player-development staff have been encouraged about the strides he’s made defensively this season.

The big league club has been using a combination of left-handed Dominic Canzone and right-handed Taylor Ward in right field since acquiring Ward from the Orioles at the Trade Deadline. But it also has Victor Robles, who’s the superior defender but has played sparingly.

Canzone has also seen a chunk of his action at designated hitter (81 games) in what’s been a breakout year, as he’s emerged as an everyday bat and one of the Mariners’ most consistent. Ward has been used at DH on most days when Canzone isn’t, as he’d recently been nursing left quad discomfort.

Of note, Montes hits left-handed -- as do many within the Mariners’ lineup. Also of note, Montes carried a 30.7% strikeout rate at Tacoma, which is another area that he’s attempted to harness throughout his player development.