MLB trade rumors: Cincinnati Reds potentially eyeing another reunion with $108 million Seattle Mariners pitcher after recent Eugenio Suarez signing

The Cincinnati Reds recently brought back third baseman Eugenio Suárez on a one-year, $15 million contract with a mutual option for 2027. The move reunited the club with one of its former power hitters and raised the question of whether Cincinnati might continue improving its roster.One idea that has circulated is a trade that would bring another familiar name back to the Reds. The proposal involves Seattle Mariners starter Luis Castillo returning to Cincinnati. The right-hander is under contract through 2027, and the Reds have enough young pitchers to make a deal possible.The suggested deal would send Luis Castillo from Seattle Mariners to Cincinnati Reds. In return, the Mariners would receive three young pitchers: Rhett Lowder, Chase Burns, and Connor Phillips.Lowder, 23, is known for his command and ability to limit mistakes. Burns, also 23, has high velocity and strong strikeout potential. Phillips, 24, gives Seattle another power arm who could work as a starter or in relief.The proposal does not involve any current Reds major leaguers. That means Cincinnati would keep its main rotation pieces, including Hunter Greene and Nick Lodolo. Under the structure of the deal, Seattle would also take on about $24 million of Luis Castillo’s 2026 salary.For Cincinnati Reds, the move would add a reliable starter to the rotation. Greene and Lodolo have strong ability but have also dealt with injuries and uneven stretches. Luis Castillo would give the Reds a veteran pitcher who can handle a full workload. Seattle Mariners would gain several young pitchers who could develop into long-term contributors. Moving Castillo’s contract would also free payroll space that could be used to address other needs on the roster, including potential infield upgrades such as Brendan Donovan.The deal would also reunite Castillo with Suárez. The two played together in Cincinnati before Castillo was traded to the Mariners in 2022.Luis Castillo remained a reliable starter for Seattle during the 2025 season. Eugenio Suárez, meanwhile, had one of the most productive power seasons of his career, hitting 49 home runs while splitting the year between Arizona and Seattle.For the Cincinnati Reds, Luis Castillo would provide an immediate improvement over untested pitchers. His 3.54 ERA and ability to pitch deep into games would help a team that was close to a playoff spot in 2025. His experience could also help a young clubhouse that includes shortstop Elly De La Cruz.The cost would be several promising pitchers from the farm system, and Castillo’s contract would increase payroll. There is also the possibility that pitching in hitter-friendly Great American Ball Park could raise his home run totals after allowing 23 in 2025.Seattle Mariners would receive three pitchers with upside and gain financial flexibility. However, trading Castillo would remove a dependable starter who regularly pitches close to 180 innings.Luis Castillo is 33 years old, stands 6-foot-3, and weighs 209 pounds. The Dominican pitcher would join a Reds roster that already includes Dominican shortstop Elly De La Cruz and Venezuelan third baseman Eugenio Suárez.The rotation would combine experience and younger pitchers with Greene (26), Lodolo (28), and Brady Singer (29) alongside Castillo.If the trade were completed, Cincinnati Reds would gain a proven top-of-the-rotation pitcher while keeping most of its current roster. That could improve the Reds’ chances of competing in the NL Central.Also read: MLB trade rumors: Los Angeles Dodgers potentially targeting $5.75 million Toronto Blue Jays left-hander in blockbuster deal to strengthen pitching depth before Opening DaySeattle Mariners would add several young pitchers and reduce payroll commitments. The main risk would be losing a starter who has provided consistent innings for the Mariners.