Seattle Mariners pitcher Luis F. Castillo throws during a game against the Houston Astros on April 9 at T-Mobile Park. Stephen Brashear-Imagn Images

Seattle Mariners Make Interesting Roster Move as They Trade Reserve SP to Baltimore Orioles

Originally posted on Seattle Mariners on SI
By Teren Kowatsch | Last updated May 8, 2025 12:15 PM ET

The Seattle Mariners starting rotation has dealt with a fair share of injuries this season. George Kirby began the season on the 15-day injured list with right shoulder inflammation and Logan Gilbert was placed on the 15-day IL with a Grade 1 right elbow flexor strain. The Mariners have had seven pitchers start games due to the various injuries. And the club dealt one of those pitchers to an American League East club on Wednesday.

Seattle traded Luis F. Castillo to the Baltimore Orioles in return for cash considerations, and he's not to be confused with three-time All-Star and former Cincinnati Reds hurler Luis M. Castillo. The Mariners designated Luis F. Castillo for assignment on May 6.

Luis F. Castillo was a relatively new addition to Seattle. He was signed by the team this January to a minor league contract with a non-roster invite to spring training. He had limited major league experience before signing with the Mariners. He made three appearances as a reliever for the Detroit Tigers in 2022 and posted a 0.00 ERA with four strikeouts in 3.2 innings pitched.

Things are starting to accelerate here in the 2nd inning for Luis F. Castillo, who fell into a bases-loaded jam after consecutive bunts then surrendered a two-run double to LaMonte Wade Jr. before recording the first out. pic.twitter.com/9rGg1w9N6G
— Daniel Kramer (@DKramer_) April 4, 2025

Castillo spent two seasons in between his stints with Detroit and Seattle in Japan's Nippon Professional Baseball. He pitched for the Chiba Lotte Mariners in 2023 and the Orix Buffaloes in 2024.

Castillo had two outings for the Mariners this season, both starts. He had a 7.71 ERA and struck out five batters in seven innings pitched. His last start was against the Houston Astros on April 9. He pitched four innings in that outing and fanned three batters. He walked five batters and allowed four runs (three earned) on six hits.

Castillo has started four games for Seattle's Triple-A affiliate, the Tacoma Rainiers, this season. He had a 5.02 ERA with 12 strikeouts in 14.1 innings pitched.

The Orioles have dealt with a horrific pitching situation in the early-going this season, with Kyle Bradish, Zach Eflin and Grayson Rodriguez each on the injured list.

This article first appeared on Seattle Mariners on SI and was syndicated with permission.

More must-reads: