Former Seattle Mariners Top Pitching Prospect Gets Another Chance, Signs MiLB Deal with Royals

Justin Dunn, who was supposed to be a big part of the Mariners rebuild of the 2020s, has latched on with the Kansas City Royals after being let go by the Chicago White Sox.

Seattle Mariners pitcher Justin Dunn (35) signs autographs before a game against the Kansas City Royals at T-Mobile Park in 2021. | Troy Wayrynen-Imagn Images

After being let go by the Chicago White Sox organization, former Seattle Mariners farmhand Justin Dunn has signed on with another organization.

According to Jaylon Thompson, he's signed a minor league deal with the Kansas City Royals.

#Royals have signed RHP Justin Dunn to a minor-league deal, per source.

— Jaylon T. Thompson (@jaylonthompson) June 6, 2025

Dunn appeared in 10 games for Triple-A Charlotte this season, going 2-3 with a 7.64 ERA. He struck out 38 batters in 33.0 innings. It was his first time in affiliated baseball since 2023, and he only threw 3.1 innings that season because of injury.

Dunn was drafted by the New York Mets in the first round of the 2016 draft out of Boston College. He was involved in a blockbuster trade before the 2019 season when he was dealt along with Jarred Kelenic from the Mets to the Mariners for Edwin Diaz and Robinson Cano.

He was then dealt again before the 2022 season from the Mariners to the Cincinnati Reds in the deal that sent Eugenio Suarez and Jesse Winker to Seattle. The New York native was supposed to be an integral part of Seattle's future but has battled ineffectiveness and injury over his career.

He made four starts for the Mariners in the 2019 season, then went 4-1 in the COVID 2020 season over 10 starts. He went 1-3 in 11 starts for the 2021 Mariners and then only made seven starts for the Reds in 2022.

Lifetime, he's 6-7 in his MLB career with a 4.44 ERA.

He was ranked the No. 91 prospect in baseball by MLB.com in 2019.

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