Luis F. Castillo Bio
Luis Felipe Castillo (born March 10, 1995) is a Dominican professional baseball pitcher who is currently a free agent. He has played in Major League Baseball (MLB) for the Detroit Tigers and Seattle Mariners and in Nippon Professional Baseball (NPB) for the Chiba Lotte Marines and Orix Buffaloes, after originally signing with the Arizona Diamondbacks as an international free agent in 2012. A right-handed pitcher, Castillo has spent more than a decade moving between minor league affiliates, MLB rosters, and top international leagues in Japan.
Across his career, Castillo has been used primarily as a starter and long reliever, logging innings in the Dominican Summer League, the Low-A and High-A levels, Double-A and Triple-A, and at the major league level in both the United States and Japan. He is also a former member of the Dominican Republic national baseball team.
Early Life and Background
Luis Felipe Castillo was born on March 10, 1995, in the Dominican Republic. Like many Dominican prospects of his generation, he grew up playing baseball at a young age and developed within a baseball culture that has produced a steady stream of major league talent. Details about his parents, siblings, and formal education have not been publicly confirmed, so those parts of his personal story remain outside the scope of this biography.
Castillo’s pathway to professional baseball followed the international signing route that is common for Dominican players. Rather than attending a four-year United States college program or being selected in the MLB amateur draft, he signed his first professional contract directly out of his home country. That agreement, reached in February 2012, launched a long climb through the Arizona Diamondbacks’ farm system.
Path to Professional Baseball
On February 16, 2012, Castillo signed with the Arizona Diamondbacks as an international free agent at the age of 16. He was assigned to the Dominican Summer League Diamondbacks, where he made his professional debut. In his first season, he went 0–9 with a 4.48 ERA in 14 starts, a difficult introduction to pro ball that is common for teenage pitchers adjusting to a full schedule.
Over the next several seasons, Castillo worked his way through the lower levels of the Diamondbacks’ system. He returned to the Dominican Summer League team the following year and posted a 3.58 ERA in 14 starts, then moved up to the rookie-level Arizona League Diamondbacks in 2014. In 2015 he recorded a 1.83 ERA across 11 appearances, signaling real progress for the young right-hander.
Luis F. Castillo Career
Early Career in the Diamondbacks System (2012–2018)
From 2016 through 2018, Castillo continued to log innings at the lower levels of the minors. He pitched for the rookie-level Missoula Osprey in 2016, the Low-A Hillsboro Hops in 2017, and split 2018 between the Single-A Kane County Cougars, Hillsboro, and Missoula. Across those three seasons he gradually trimmed his ERA, finishing the 2018 campaign with a combined 2.41 ERA in 24 appearances.
His strongest minor league season came in 2019, when he pitched for the High-A Visalia Rawhide and went 9–0 with a 3.81 ERA in 43 appearances. That undefeated record marked him as one of the more effective relievers in the California League that year and put him on the radar for a future promotion.
Arizona Diamondbacks Continued and MiLB Return (2019–2021)
Castillo did not appear in a game in 2020 after the minor league season was canceled because of the COVID-19 pandemic. He returned in 2021 and was assigned to the Double-A Amarillo Sod Poodles before receiving a midseason promotion to the Triple-A Reno Aces in June. He finished the year with a combined 4.72 ERA across 29 appearances between the two affiliates. Following the season, on November 7, 2021, Castillo elected minor league free agency.
Detroit Tigers and MLB Debut (2022)
On February 1, 2022, Castillo signed a minor league contract with the Detroit Tigers and was assigned to the Triple-A Toledo Mud Hens to begin the year. On August 6, the Tigers selected his contract and promoted him to the major leagues for the first time. That night he made his MLB debut, becoming a major league pitcher.
In three scoreless appearances for Detroit, Castillo struck out four batters over 3⅔ innings. On November 10, 2022, he was removed from the Tigers’ 40-man roster, sent outright to Triple-A Toledo, and elected free agency the same day.
NPB Stint with the Chiba Lotte Marines (2023)
On December 16, 2022, Castillo signed with the Chiba Lotte Marines of Nippon Professional Baseball. In 12 appearances during the 2023 NPB season, he went 3–3 with a 3.12 ERA and 34 strikeouts across 49 innings of work. He became a free agent after the season.
Orix Buffaloes in Japan (2024)
On January 16, 2024, Castillo signed with the Orix Buffaloes of NPB. In 15 appearances that year, he posted a 3–5 record and a 2.96 ERA, striking out 74 batters over 94⅓ innings. He became a free agent once again at the end of the Japanese campaign.
Seattle Mariners and Baltimore Orioles (2025)
On January 28, 2025, Castillo signed a minor league contract with the Seattle Mariners that included an invitation to spring training. On April 4, the Mariners selected his contract and added him to their active roster. In Seattle, he picked up the nickname “The Pebble,” a playful nod to teammate Luis Castillo, whose own nickname is “La Piedra,” Spanish for “The Rock.” In two starts for the Mariners, Castillo struggled to a 7.71 ERA with five strikeouts over seven innings, and on April 10 he was optioned to the Triple-A Tacoma Rainiers before being designated for assignment on May 6.
On May 7, 2025, the Mariners traded Castillo to the Baltimore Orioles in exchange for cash considerations. After two rehabilitation starts for the rookie-level Florida Complex League Orioles, he was designated for assignment on June 29, cleared waivers, and was sent outright to the Triple-A Norfolk Tides on July 7. On October 1, 2025, Castillo elected free agency.
International Career
Castillo represented the Dominican Republic national baseball team at the 2020 Summer Olympics, which were contested in 2021. In five relief appearances for his country, he went 1–1 with a 6.75 ERA.
Luis F. Castillo Family
Publicly verified information about Luis Felipe Castillo’s parents, spouse, and children is not currently available. As a result, this section is limited to what is on the public record, and further personal details are intentionally omitted.
2025 Season Performance
Castillo’s 2025 campaign was a turbulent journey between three organizations. He opened the year by signing with the Seattle Mariners in late January, reached the major league roster in early April, and made two starts before being optioned to Triple-A Tacoma and later designated for assignment. His brief MLB stint with Seattle produced a 7.71 ERA over seven innings with five strikeouts.
A quick trade to the Baltimore Orioles on May 7 gave Castillo a fresh opportunity, but a pair of rehab outings in the Florida Complex League led to another designation for assignment in late June. He cleared waivers and reported to the Triple-A Norfolk Tides in July before electing free agency on October 1, 2025. With free agency in hand, Castillo entered the offseason looking for a new contract.