Mariners Send Prospect to St. Louis as Part of Offseason Overhaul
The Seattle Mariners traded switch pitcher Jurrangelo Cijntje to the St. Louis Cardinals on Monday as part of a three-team deal that also sent third baseman Ben Williamson to the Tampa Bay Rays. In return, the Mariners acquired 2025 All-Star Brendan Donovan, addressing several holes in their lineup heading into spring training.
Cijntje, 22, joins a Cardinals organization looking to develop the rare ambidextrous pitcher further after his first professional season. The Curaçaoan prospect was selected 15th overall by Seattle in the 2024 MLB Draft after a standout college career at Mississippi State, where he earned second-team All-American honors in 2024.
Shifting to Right-Handed Focus
The trade comes shortly after the Mariners announced plans for Cijntje to pitch exclusively right-handed during spring training and the foreseeable future. While his ambidextrous ability generated significant attention, Mariners General Manager Justin Hollander said the organization believes his highest ceiling lies as a right-handed starter.
“We think that’s his highest ceiling, as a right-handed starter,” Hollander said during the team’s FanFest. “For the start of camp and for the foreseeable future, he’s going to pitch right-handed in games.”
The data supports this strategic shift. Right-handed batters have struggled against Cijntje when he throws from his dominant side, posting just a .209/.298/.364 batting line. In right-on-right matchups, he’s even more dominant, limiting righty hitters to a .166/.224/.256 average with 73 strikeouts against nine walks. From his left side, however, opponents hit .284/.531/.577 with nine home runs.
First Professional Season Numbers
Cijntje finished his inaugural professional campaign with the Mariners’ Double-A affiliate in 2025 posting a 5-7 record with a 3.99 ERA across 26 games. He struck out 120 batters over 108â…“ innings pitched while posting a 1.22 WHIP. MLB.com ranked him as the 91st best prospect heading into the 2026 season.
Donovan Fills Holes for Mariners
The acquisition of Donovan represents a significant boost to Seattle’s roster. The versatile infielder earned his second All-Star selection in 2025 and addresses multiple positions for a Mariners team looking to compete in the American League. The trade addresses the positional surplus created by Donovan’s arrival, with Williamson moving to Tampa Bay to complete the deal.
Cijntje, who committed to Mississippi State after being selected in the 18th round by Milwaukee in 2022, will look for a fresh start with the Cardinals organization while focusing on maximizing his potential as a right-handed pitcher.
