The Seattle Mariners came tantalizingly close to history in 2025. After clinching just their fourth division title, they marched all the way to the American League Championship Series, only to fall short against a surging Toronto Blue Jays squad.
Still, the campaign marked a major step forward for a franchise that’s been knocking on the door for years. Now, with a largely intact core and a clear window to contend, Seattle’s front office is looking to make targeted upgrades-not a rebuild, not a splash for splash’s sake, but smart, surgical moves to address key needs.
One of those needs? Left-handed relief. And that’s where JoJo Romero comes in.
According to multiple reports, the Mariners have been engaged in ongoing trade discussions with the St. Louis Cardinals throughout the offseason, with Romero firmly on their radar.
The 29-year-old southpaw is coming off a career-best season, and it’s easy to see why Seattle is interested. In 2025, Romero made 65 appearances out of the Cardinals’ bullpen, tossing 61 innings with a sparkling 2.07 ERA and 59 strikeouts.
He posted a 1.7 bWAR and consistently delivered in high-leverage spots. Simply put, he was one of the most effective lefty relievers in the National League last year.
Romero just signed a $4.25 million pre-arbitration deal with St. Louis, and he’s entering the final year of club control. That makes him both affordable and appealing for a contender looking to solidify the back end of its bullpen without mortgaging the future.
But Romero isn’t the only Cardinal drawing Seattle’s attention.
Infielder Brendan Donovan is reportedly the Mariners’ top trade target this winter. The 28-year-old earned his first All-Star nod in 2025 despite missing time due to injury, and he’s exactly the type of player the Mariners covet: versatile, consistent, and controllable.
Donovan slashed .287/.353/.422 across 118 games last season, good for a 118 OPS+ and 2.7 bWAR. He’s primarily a second baseman-where Seattle has a vacancy following Jorge Polanco’s departure-but he’s also capable at third base and has some outfield experience.
That kind of defensive flexibility is gold in today’s game, especially for a team that values matchup-based lineup construction.
Seattle isn’t alone in its pursuit. Donovan is drawing interest from multiple clubs, and with the Cardinals clearly in a retooling phase under new team president Chaim Bloom, it’s no surprise that they’re listening.
St. Louis has already moved several veterans this offseason, including Sonny Gray and Willson Contreras to Boston and Nolan Arenado to Arizona.
The writing’s on the wall: Donovan could be next.
The Cardinals just locked him into a $5.8 million deal for 2026 to avoid arbitration-slightly above projections-but that doesn’t mean he’s off the market. If anything, it makes him an even more attractive trade chip for teams like the Mariners, who are looking for immediate impact without taking on long-term financial risk.
For Seattle, these aren’t blockbuster moves. They’re the kind of calculated additions that contenders make to push from “almost” to “all the way.”
Romero would deepen a bullpen that already has some bite. Donovan would plug a hole in the infield while giving the Mariners lineup flexibility and a high-contact bat.
Both would fit seamlessly into a roster that’s built to win now, without disrupting the chemistry that helped fuel last season’s run.
The Mariners have been patient, methodical, and increasingly aggressive under their current regime. If these talks with St. Louis bear fruit, they might just be the final pieces to a puzzle that’s nearly complete.