Reds Trade Luis Castillo to Mariners for Massive Prospect Haul

On Friday night, the Seattle Mariners nabbed arguably the best starting pitcher on this year’s trade market, acquiring right-hander Luis Castillo from the Cincinnati Reds for four prospects, including Just Baseball’s No. 21 overall prospect, shortstop Noelvi Marte. The other prospects are shortstop Edwin Arroyo and pitchers Levi Stoudt and Andrew Moore.

Luis Castillo

Castillo, 29, is throwing to a career-best 2.86 ERA over 14 starts so far this year. Across 85 innings, he has amassed 90 strikeouts and is allowing just under seven hits-per-nine innings.

Castillo owns a career 3.62 ERA across six Major League seasons. After leading the National League in starts (33), losses (16), and walks issued (75) in 2021, the right-hander has rebounded mightily with his command and has looked as sharp as in his career after missing the first month of the season with an injury.

The two-time All-Star, including this year, has registered the lowest walk rate (8%) of his career since he was a 25-year-old in 2018. While opponents are hitting fewer ground balls and more line drives against him this year as opposed to recent years, opposing hitters are slashing .201/.274/.318 (.592 OPS) this season, which are all career-bests.

Much of the intrigue surrounding Castillo at the deadline had to do with his contract situation. Yes, a 97 mile-per-hour fastball and a changeup that opponents hit .196 against is the largest part of the story, but Castillo has another year of control, his final year of arbitration, before hitting free agency after next season. Seattle may very well have found an extension candidate in Castillo, who will turn 30 this December.

The Return to Cincinnati

Headlining the crop of prospects returning to the Reds is Noelvi Marte. Marte, the top prospect in the Mariners system, is hitting .275 with an .825 OPS, 19 doubles, 15 home runs, and 13 stolen bases in 85 games with Seattle’s High-A affiliate, the Everett AquaSox.

Edwin Arroyo, the No. 3 prospect in Seattle’s organization according to MLB Pipeline, is slashing .316/.385/.514 (.899 OPS) with 13 home runs and 21 stolen bases in Low-A. Seattle’s second round pick in last year’s MLB Draft, Arroyo is still just 18 years old after being one of the youngest players drafted in 2021. The native Puerto Rican is a switch hitter who has a nice combination of power, bat-to-ball, and speed to accompany his defensive fluidity.

Stoudt, the Mariners’ third round pick in 2019 out of Lehigh, was Seattle’s second-best pitching prospect following the graduation of George Kirby, only behind right-hander Emerson Hancock. Despite an ERA over 5.00 in 18 starts with Double-A Arkansas, Stoudt has an overpowering fastball that can reach the upper-90s.

Moore is a tall right handed pitcher who has thrown to a sub-2.00 ERA out of the bullpen in Low-A so far this season. The strikeout numbers are piling up for Moore, who has fanned 58 hitters in just 32.1 innings (16.1 K/9). Moore joins the Reds’ first round pick this year, Cam Collier, as Chipola College alumni in Cincinnati’s system.