Cardinals— The Seattle Mariners are nearing completion of a significant roster move that could reshape their lineup ahead of the 2026 season. According to sources familiar with the negotiations, the Mariners are finalizing a trade that would bring St. Louis Cardinals infielder/outfielder Brendan Donovan to Seattle as part of a complex three-team deal that also includes the Tampa Bay Rays.
While the foundational structure of the trade has already been agreed upon by all parties involved, the transaction is not yet official. Team officials are currently reviewing medical records and completing the administrative process of informing the players affected by the deal. These final steps are considered procedural, and barring any unforeseen complications, the trade is expected to be completed in the near future.
If finalized, the acquisition of Donovan would represent one of the Mariners’ most impactful personnel moves in recent years, addressing multiple roster needs at once. Seattle has been actively seeking a versatile, high-contact hitter capable of setting the tone at the top of the lineup, and Donovan fits that profile exceptionally well.
A Proven, Versatile Performer
Donovan, who will enter his age-29 season in 2026, has steadily built a reputation as one of Major League Baseball’s most reliable and adaptable players. A first-time All-Star in 2025, Donovan has consistently demonstrated value both offensively and defensively since making his MLB debut with the Cardinals in 2022.
Originally known for his defensive flexibility, Donovan quickly proved he was more than just a utility option. During his rookie campaign in 2022, he earned a Gold Glove Award for utility players, recognizing his ability to play multiple positions at a high defensive level. Over the past four seasons, he has logged significant time at second base, third base, first base, and in the corner outfield spots, making him a manager’s dream and a valuable chess piece in daily lineup construction.
Offensively, Donovan has been equally impressive. Across four seasons with St. Louis, he has compiled a career slash line of .282/.361/.411, good for a .772 OPS. His 117 OPS+ indicates that he has been 17 percent better than league average offensively over that span, a notable achievement given the premium placed on power over contact in today’s game.
Donovan’s offensive production includes 40 home runs, 97 doubles, and a total of 11.1 Baseball-Reference WAR, underscoring his consistency and all-around contribution. Rather than relying solely on power, he has carved out success through plate discipline, bat-to-ball skills, and a mature approach that allows him to handle pitchers of all types.
From a financial and roster-planning perspective, Donovan represents a highly appealing asset for the Mariners. He is currently in his second year of arbitration eligibility and agreed to a $5.8 million contract for the 2026 season with the Cardinals. Assuming the trade is completed, Seattle will inherit that contract and retain two full seasons of club control, with Donovan set to reach free agency after the 2027 campaign.
For a player of Donovan’s caliber and versatility, that level of control at a relatively modest salary offers significant value, particularly for a Mariners organization that has shown a willingness to spend strategically rather than recklessly.
One of Donovan’s most appealing attributes for Seattle is his ability to get on base. He owns a career on-base percentage of .361, a figure that immediately places him among the best table-setters in the league. That skill set makes him a prime candidate to bat at or near the top of the Mariners’ lineup, a spot that has been in flux in recent seasons.
Seattle has often relied heavily on power while struggling with consistency and on-base production at the top of the order. Donovan’s disciplined approach, combined with his low strikeout tendencies, could help stabilize the offense and create more opportunities for the team’s middle-of-the-order hitters.
In 2025, Donovan posted a strikeout rate of just 13 percent, one of the lowest marks in all of Major League Baseball. At a time when strikeouts continue to rise across the league, his ability to put the ball in play stands out as a valuable counterbalance to the more swing-and-miss profiles elsewhere on the roster.
That same season, his 119 weighted runs created plus (wRC+) ranked fifth among regular second basemen, further highlighting his offensive efficiency relative to his peers.
If Donovan slots into the Mariners’ everyday lineup as expected, Seattle could field one of the most accomplished top halves of a batting order in the American League. The projected top five hitters — Brendan Donovan, Julio RodrĂguez, Cal Raleigh, Josh Naylor, and Randy Arozarena — have all earned All-Star selections within the past two seasons.
That concentration of proven talent represents a significant step forward for a franchise that has often relied on youth and projection rather than established production. Donovan’s presence would help balance the lineup by adding a high-contact, high-OBP hitter ahead of Seattle’s power threats, potentially unlocking more run-scoring opportunities throughout the game.
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Julio RodrĂguez, in particular, could benefit from hitting behind a player with Donovan’s on-base skills. With more runners on base, opposing pitchers would be forced to challenge RodrĂguez more frequently, reducing the likelihood of constant pitch-around situations.
The Mariners’ interest in Donovan became more pronounced following the departure of Jorge Polanco, who signed with the New York Mets in free agency. Polanco had served as a middle-of-the-order presence and was known primarily for his power production. While Donovan does not replicate Polanco’s slugging profile exactly, advanced metrics suggest that he offers comparable — if not superior — overall value.
According to FanGraphs, Donovan recorded a 2.9 fWAR in 2025, surpassing Polanco’s 2.6 fWAR during the same season. That comparison illustrates how Donovan’s combination of defense, on-base ability, and positional flexibility can offset a modest drop in raw power.
In many ways, Donovan represents a philosophical shift rather than a direct replacement. Where Polanco provided power and run production, Donovan offers efficiency, versatility, and lineup balance — qualities the Mariners have prioritized as they attempt to build a more sustainable offensive model.
Defensive Flexibility and Roster Impact
Beyond the numbers, Donovan’s ability to play multiple positions could have ripple effects throughout the Mariners’ roster. His presence gives the coaching staff greater flexibility to rest players, manage matchups, and cover injuries without sacrificing production.
Whether deployed at second base, in the outfield, or elsewhere, Donovan has shown he can maintain above-average defense while contributing offensively. That adaptability is especially valuable over the course of a 162-game season, where depth and durability often determine postseason success.
While the Mariners have consistently fielded competitive pitching staffs, offensive inconsistency has often been the limiting factor in their postseason pursuits. Acquiring a player like Donovan signals an effort to address that imbalance without sacrificing long-term flexibility.
At 29 years old, Donovan is firmly in his prime, offering immediate impact without the risk associated with aging veterans. His contract status, skill set, and clubhouse reputation all align with Seattle’s current competitive window.
If the trade is finalized as expected, the Mariners will have added a player who not only improves their on-field performance but also complements the existing core in meaningful ways.
For now, the deal remains pending, with teams continuing to finalize medical reviews and logistical details. Once completed, the trade would mark another important step in the Mariners’ ongoing effort to transform themselves from a promising contender into a consistent postseason force.
Should Donovan officially arrive in Seattle, expectations will be high — but based on his track record, versatility, and approach, he appears well-equipped to meet them.
