Seattle Mariners Deal Minor League Pitcher For Major League Bullpen Help

Mariners No. 21 prospect Jeter Martinez was traded to the Pittsburgh Pirates in return for left-handed veteran reliever Caleb Ferguson on Wednesday.

A Seattle Mariners Armed Forces Day hat is pictured in the dugout before a game against the Atlanta Braves on May 20, 2023, at Truist Park. | Brett Davis-Imagn Images

The MLB trade deadline is set to take place at 3 p.m. PT on July 31. With one day away until the trade deadline, a lot of eyes are glued to what the Seattle Mariners and team president of baseball operations Jerry Dipoto will do.

The Mariners entered Wednesday tied to several high-leverage relievers in the trade market. They made that addition to the bullpen and acquired left-handed reliever Caleb Ferguson from the Pittsburgh Pirates on Wednesday.

Seattle sent minor league pitcher Jeter Martinez to the Pirates in return for the veteran reliever.

Ferguson is a solid addition to the Mariners bullpen. He has a 3.74 ERA with 34 strikeouts in 43.1 innings pitched across 45 appearances this season.

Martinez is ranked the organization's No. 21 prospect, according to MLB Pipeline.

Martinez was signed by Seattle as an international free agent out of Mexico on Jan. 15, 2023. He spent 2023 in the Dominican Summer League and 2024 in the Arizona Complex League.

This season, Martinez has posted a 6.18 ERA with 60 strikeouts in 62.2 innings pitched across 16 starts with the Single-A Modesto Nuts.

The Mariners are trading RHP Jeter Martinez to the Pirates for LHP Caleb Ferguson, per @JonathanMayo

Martinez ranked No. 21 in Seattle's system.

Big arm who has been up to 100 mph in the past but has struggled with strike-throwing. pic.twitter.com/qF2hEbLGfm

— Baseball America (@BaseballAmerica) July 30, 2025

MLB Pipeline had the following scouting report on Martinez:

In Martinez's two stops heading into 2025, the Dominican Summer League and the Arizona Complex League, he showed his raw stuff can get hitters out -- when he knows where it’s going. He struggled to find consistency for much of his first taste of full-season ball this year, but was having his best month in July when he was sent to the Pirates in the Caleb Ferguson trade.

Related Minor League Baseball stories

MARINERS OUTFIELD PROSPECT WINS MINOR LEAGUE PLAYER OF THE WEEK: Tai Peete received a weekly honor after a dominant stretch that included multiple home runs. CLICK HERE

PROSPECT GURU PRAISES TOP MARINERS PROSPECT AFTER WEB GEM PLAY: Joe Doyle, a notable prospect analyst, commended the Mariners top-ranked minor leaguer Colt Emerson for his growth on defense. CLICK HERE

MARINERS OUTFIELDER ON TORRID STRETCH FOR HIGH-A EVERETT AQUASOX: Outfield prospect Tai Peete has continued to show off his power for High-A club this week. CLICK HERE

Follow Minor League Baseball On SI on social media

You can also follow Teren Kowatsch on social media on Twitter @Teren_Kowatsch.