Mariners Acquire Cooper Criswell from Mets in Cash Deal
In a strategic move aimed at strengthening their pitching staff, the Seattle Mariners have announced the acquisition of right-handed pitcher Cooper Criswell from the New York Mets. The deal, which involves cash considerations, comes as part of the Mariners' efforts to fine-tune their roster ahead of the upcoming MLB season.
Key Details of the Trade
According to an official announcement from Mariners Executive Vice President & General Manager of Baseball Operations Justin Hollander, the acquisition of Criswell necessitates a corresponding move. Left-handed pitcher Jhonathan Díaz has been designated for assignment, ensuring the Mariners' 40-man roster remains at its full capacity of 40 players.
Cooper Criswell's MLB Career
Criswell, 29, has had a varied career in Major League Baseball, appearing in parts of five seasons with three different teams. In the 2025 season, he played in seven games for the Boston Red Sox, starting one of them. During his tenure with the Red Sox, Criswell registered a 1-0 record with a 3.57 ERA, giving up seven earned runs over 17.2 innings pitched.
Before joining the Red Sox, Criswell was claimed off waivers by the New York Mets on December 5, 2025, following his stint with the Red Sox. However, the Mets designated him for assignment on January 21, 2026, paving the way for the Mariners to acquire his services.
Criswell was originally drafted by the Los Angeles Angels in the 13th round of the 2018 MLB First-Year Player Draft. Over his MLB career, he has compiled an 8-7 record with a 4.48 ERA, allowing 77 earned runs over 154.2 innings pitched in 45 games, including 21 starts.
Jhonathan Díaz's Journey
In the corresponding move, the Mariners have designated left-handed pitcher Jhonathan Díaz for assignment. Díaz, 29, made just one appearance for the Mariners in 2025, and the majority of his playing time came at the Triple-A level. He led the Pacific Coast League with a 4.15 ERA, giving up 64 earned runs over 138.2 innings in 27 games, 26 of which were starts.
Over two seasons with the Mariners, Díaz has appeared in six games, posting a 0-1 record with a 4.09 ERA. His MLB career spans parts of five seasons with the Angels and Mariners, during which he has made 17 appearances, including seven starts.
Born in Valencia, Venezuela, Díaz has also had a successful minor league career, posting a 73-47 record with a 3.81 ERA over 10 minor league seasons across various organizations. He was originally signed by the Red Sox as an international free agent on July 2, 2013.
Strategic Implications for the Mariners
The acquisition of Criswell adds depth to the Mariners' pitching rotation, providing manager Scott Servais with another option for both starting and relief roles. Criswell's versatility, having experience in both starting and relief roles, makes him a valuable asset as the Mariners look to contend in a highly competitive American League West division.
With the addition of Criswell, the Mariners are signaling their intent to be serious contenders in the upcoming season. The trade also underscores the team's willingness to make bold moves to enhance their roster, even if it means parting with players like Díaz who could not find a consistent spot in the MLB lineup.
What Lies Ahead for Criswell
For Criswell, the move to Seattle represents an opportunity to secure a more prominent role within a Major League team. Having experienced the highs and lows of MLB waivers, Criswell will be eager to prove his worth and solidify his position in the Mariners' pitching rotation.
As the Mariners prepare for the 2026 season, all eyes will be on Criswell to see if he can translate his past performance into consistent contributions for his new team. The Mariners' fans and management will be watching closely as they hope to see the right-hander deliver the kind of performance that can help push the team to new heights.
Conclusion
The Mariners' acquisition of Cooper Criswell is a testament to the team's commitment to building a competitive roster. With the move, the Mariners have added a pitcher with a wealth of experience and a track record of performance, both in the MLB and the minor leagues. As the season approaches, it will be interesting to see how Criswell integrates into the Mariners' pitching staff and the impact he can make on the team's overall success.
