The Seattle Mariners and Baltimore Orioles have reportedly been engaged in trade discussions centered around Mariners’ veteran starting pitcher Luis Castillo. This development, reported by MLB Network’s Jon Morosi, suggests both American League teams are seeking to address their roster needs as the offseason progresses.
For the Mariners, the infield remains a significant area of concern with just over a month until Spring Training begins. The team has been searching for solutions at second and third base, a first baseman to complement Luke Raley, and additional bullpen depth. Despite entering the offseason with these pressing needs, Seattle has only extended offers to two players—Carlos Santana and Hye-seong Kim—both of whom signed with other teams. These setbacks have amplified the Mariners’ urgency to explore alternative options, including potential trades.
The Orioles, meanwhile, are seeking to bolster their starting rotation, which has been a priority this offseason. Baltimore has been unable to secure several high-profile pitchers, including Corbin Burnes, Max Fried, Blake Snell, Walker Buehler, and Garrett Crochet, and has not been linked to Japanese ace Roki Sasaki. With few marquee options left, the Orioles appear to be targeting Castillo as a way to strengthen their rotation.
In these trade talks, Baltimore’s roster includes several players who could address Seattle’s deficiencies. One intriguing candidate is Jordan Westburg, a young and affordable third baseman under team control for several years. Westburg had a strong 2024 season, hitting .264 with 18 home runs and 63 RBIs. Another potential trade piece is first baseman Ryan Mountcastle, who hit .271 with 13 home runs and 63 RBIs last season. Mountcastle’s right-handed bat would make him a natural platoon partner for Raley, though his higher salary ($6 million estimated in 2025) and shorter team control (free agency after 2026) may make him a less attractive option for Seattle.
There has also been speculation about the Orioles including top prospect Coby Mayo in a deal for Castillo. However, the Mariners’ reported rejection of a trade offer from the Boston Red Sox—including first baseman Triston Casas and designated hitter Masataka Yoshida—indicates Seattle may be reluctant to move Castillo for unproven talent alone. Mayo, though highly regarded, may not be enough to entice the Mariners, given their clear desire for established major league contributors.
Both teams are under pressure to make moves after an offseason that has not gone as planned. The Mariners’ unmet infield needs and the Orioles’ rotation concerns create an opportunity for a mutually beneficial trade. Castillo, a proven starting pitcher, could provide the stability Baltimore seeks, while Seattle could acquire assets to fill its infield gaps and potentially strengthen its lineup.
This latest rumor adds to ongoing speculation surrounding Seattle’s offseason plans. Previous reports have proposed trade scenarios involving Castillo, such as a potential deal with the San Francisco Giants for first baseman LaMonte Wade Jr. Additionally, the Mariners have been linked to other third base options and have been rumored to explore a trade for Luis Arraez, a multi-time batting champion with the San Diego Padres.
As trade talks between the Mariners and Orioles continue, both teams will aim to strike a deal that aligns with their respective needs and ambitions. A potential agreement involving Luis Castillo would have significant implications for both organizations as they prepare for the 2025 season.
