Mariners use the 40-man roster deadline to add to their stockpile of electric arms

The Seattle Mariners had themselves a busy day on Tuesday. Holding a press conference with Josh Naylor in celebration of his five-year, $92.5 million deal was just the start, as they then had to get to work finalizing their 40-man roster ahead of the Rule 5 Draft.

The Mariners used the occasion to make two notable moves, beginning with a trade that saw them acquire right-hander Alex Hoppe from the Boston Red Sox in exchange for catcher Luke Heyman. In a corresponding move, the Mariners designated left-hander Taylor Saucedo for assignment.

If Heyman's name rings a bell, it might be because the Mariners just drafted him out of the University of Florida in the 14th round of this year's draft. He had a .975 OPS and 13 homers in 49 games for the Gators this season before an injury ended his season in May. He has yet to make his pro debut.

Mariners add a new electric arm as they set their 40-man roster ahead of the Rule 5 Draft

Hoppe is a 26-year-old who was a sixth-round pick by the Red Sox out of UNC Greensboro in 2022. He hasn't found much success in the minors, pitching to a 4.76 ERA with 192 hits and 88 walks allowed in 176.0 innings.

The stuff is there for Hoppe, however. Eric Longenhagen of FanGraphs rated his fastball as a 60 on the 20-80 scouting scale back in June. It sat at an average of 98.1 mph at Triple-A Worcester this year, with a max speed of 100.6 mph. He also relies on a cutter that he can get up to 96 mph.

There could be something here if the Mariners find a way to get Hoppe in the strike zone more consistently, which is kind of the organization's whole thing. "Dominate the zone" is the saying, and the Mariners practice what they preach. Only two clubs at the big league level threw more pitches in the strike zone than they did this year.

If the Mariners can get Hoppe in the strike zone more often, he could be a weapon out of their bullpen as soon as next year. Ideally, he'll emerge as a leverage guy for Dan Wilson to use in tandem with Andrés Muñoz, Matt Brash, Gabe Speier and Eduard Bazardo.

As explained by Mark Powell of FanSided, the other important part of Tuesday's deadline involved teams choosing which players they wanted to protect from the Rule 5 Draft, which is set for December 10. Players signed at 18 years old or younger must be added to a club's 40-man roster within five years, while anyone signed at 19 or older must be added within four years. If they're not, they are eligible to be drafted by other organizations.

Six prospects in the Mariners' top 30 for MLB Pipeline had to be protected by Tuesday's deadline, and the Mariners chose not to select any of them for their 40-man roster. That means the following players (with their MLB Pipeline organizational ranks) are now eligible for the Rule 5 Draft:

• RHP Michael Morales: No. 18
• RHP Marcelo Perez: No. 19
• 1B/3B Luis Suisbel: No. 20
• OF Carlos Jimenez: No. 27
• OF Victor Labrada: No. 29
• RHP Tyler Cleveland: No. 30

Cleveland is a guy we recently covered on account of how his funky delivery more than makes up for his lack of velocity. Suisbel is coming off a 23-homer season for High-A Everett. Morales was meant to be a projectable righty when the Mariners drafted him in the third round out of high school in 2021, but the top-shelf stuff never really came.

Saucedo, meanwhile, had his career take a turn for the worse this year after serving as a reliable lefty out of Seattle's bullpen in 2023 and 2024. He posted a 7.43 ERA in 10 appearances for Seattle, yet was due for a modest raise to $1.1 million in arbitration. By DFA'ing him, the Mariners have effectively already punted on tendering him a contract for 2026.