Gregory Santos Bio
Gregory Omar Santos, born August 28, 1999, is a Dominican professional baseball pitcher currently in the San Francisco Giants organization. He has previously played in Major League Baseball (MLB) for the Chicago White Sox and Seattle Mariners. Santos signed with the Boston Red Sox as an international free agent in 2015 and has since developed through several minor league levels before reaching the major leagues.
A right-handed relief pitcher, Santos has built his career as a hard-throwing bullpen arm, with stints across the Dominican Summer League, multiple Single-A affiliates, Triple-A Sacramento, and three MLB organizations. He is recognized for his prospect pedigree, his mid-90s fastball, and his journey through the minors before establishing himself at the highest level.
Early Life and Background
Gregory Omar Santos was born on August 28, 1999, in the Dominican Republic. Growing up in a country with a deep baseball tradition, he was drawn to the sport from an early age, following a path that has produced numerous Major League Baseball stars from the island. The Dominican Republic has long served as a fertile ground for international talent, and Santos entered that pipeline as a teenager.
On August 28, 2015, the same day he turned 16, Santos signed with the Boston Red Sox as an international free agent for $275,000. That signing marked the official start of his professional career and moved him into the Red Sox player development system. He began his journey in the Dominican Summer League, where Boston’s Latin American programs prepare young arms for the rigors of professional baseball.
Path to Baseball
Santos began his professional climb in 2016 with the Dominican Summer League Red Sox, posting a 3–3 record with a 4.17 ERA and 25 strikeouts over 41 innings. The following year, he appeared in eight starts for the DSL Red Sox, going 2–0 with a 0.89 ERA and 24 strikeouts across 30 and one-third innings, signaling his potential as a future bullpen arm.
On July 26, 2017, Santos was traded, along with Shaun Anderson, to the San Francisco Giants in exchange for Eduardo Núñez. He split the rest of that season between the DSL Red Sox and the Dominican Summer League Giants, going a combined 3–0 with a 1.29 ERA and 41 strikeouts over 49 innings. The trade set the stage for his continued development within the Giants organization and eventually led him to the United States.
Gregory Santos Career
Early Career (2015–2020)
Santos spent his earliest professional seasons in the Dominican Summer League before advancing to the short-season Northwest League with the Salem-Keizer Volcanoes in 2018. That year, he posted a 2–5 record with a 4.53 ERA over 49 and two-thirds innings and was named a Northwest League mid-season All Star. The honor reflected his standing as one of the league’s notable young pitching prospects.
In 2019, Santos played for the Augusta GreenJackets, going 1–5 with a 2.86 ERA over 34 and two-thirds innings before missing the second half of the season due to shoulder issues. He did not appear in any games in 2020 after the minor league season was canceled because of the COVID-19 pandemic. On November 20, 2020, the Giants added Santos to their 40-man roster to protect him from the upcoming Rule 5 draft, a sign that he remained a prospect of organizational importance.
San Francisco Giants Breakthrough (2021–2022)
On April 22, 2021, the San Francisco Giants promoted Santos to the major leagues for the first time. He made his MLB debut that day against the Miami Marlins, pitching a scoreless inning of relief and becoming the sixth-youngest player in the National League at the time. In that appearance, he recorded his first two Major League Baseball strikeouts, punching out Magneuris Sierra and Jazz Chisholm Jr., before being optioned to the Giants’ alternate site in Sacramento on April 28 to make room for outfielder Mike Tauchman.
On June 29, 2021, Santos was suspended 80 games after testing positive for the banned steroid Stanozolol, which kept him off the mound for a significant stretch. He returned to play in the Arizona Fall League for the Scottsdale Scorpions, going 0–1 with a 4.15 ERA in 10 relief appearances while being named an Arizona Fall League Rising Star. In 2022, he combined for a 1–2 record with one save and a 4.63 ERA in 35 games between Sacramento and the ACL Giants Black, while also making two brief relief appearances for the Giants at the major league level. On December 19, 2022, he was designated for assignment following the signing of Sean Manaea.
Chicago White Sox Era (2023)
On December 22, 2022, Santos was traded to the Chicago White Sox in exchange for minor league pitcher Kade McClure. The move gave him a fresh opportunity in a new organization, and he seized it during the 2023 season. Santos made 60 relief appearances for the White Sox, posting a 3.39 ERA with 66 strikeouts and 5 saves across 66 and one-third innings pitched. His performance established him as a reliable late-inning option and represented his most extensive major league workload to that point in his career.
Seattle Mariners Era (2024–2025)
On February 3, 2024, the Chicago White Sox traded Santos to the Seattle Mariners in exchange for right-handed pitcher Prelander Berroa, outfielder Zach DeLoach, and a Round B Competitive Balance draft pick later used to draft Blake Larson. He began the 2024 season on the injured list with a right lat strain and was transferred to the 60-day injured list on April 25 before being activated on July 8. In eight appearances for Seattle that year, Santos recorded a 4.91 ERA with six strikeouts across seven and one-third innings of work.
In 2025, Santos made another eight appearances for the Mariners, compiling a 1–1 record and 5.14 ERA with no strikeouts over seven innings. On April 25, 2025, he was placed on the 15-day injured list due to right knee inflammation, and it was announced that he would require cleanup surgery to repair cartilage. He was transferred to the 60-day injured list on April 29 and, on November 21, was non-tendered by Seattle, making him a free agent.
San Francisco Giants Return (2025–Present)
On December 17, 2025, Santos signed a minor league contract with the San Francisco Giants, returning to the organization that originally developed him in the United States. He was assigned to the Triple-A Sacramento River Cats to begin the regular season, recording a 2.45 ERA with six strikeouts and three saves over eight appearances. On April 29, 2026, the Giants selected his contract, adding him to their active major league roster once again.
Driving Style and Strengths
Gregory Santos is known for a power-pitching profile built around a mid-90s fastball that plays well in high-leverage relief roles. His strikeout tendencies in the minor leagues, including 41 strikeouts over 49 innings in 2017 and 66 strikeouts in 66 and one-third innings with the White Sox in 2023, reflect his ability to miss bats at every level. As a reliever, he has been deployed in late-inning situations and has demonstrated the composure needed to handle high-pressure major league environments.
Notable Events and Milestones
Among the defining moments of Santos’s career was his MLB debut on April 22, 2021, against the Miami Marlins, when he became the sixth-youngest player in the National League and recorded his first two major league strikeouts. He was also named a Northwest League mid-season All Star in 2018 and an Arizona Fall League Rising Star in 2021. His 2023 season with the Chicago White Sox, in which he recorded 5 saves across 60 relief appearances, stands as his most productive major league campaign to date.
Gregory Santos Career Wins
Gregory Santos has accumulated wins and saves across multiple levels of professional baseball, from the Dominican Summer League through Major League Baseball. While most of his victories came during his minor league development, his major league work has been centered on relief appearances and saves rather than traditional wins.
MLB Highlights
Through May 9, 2026, Santos had compiled a 3–6 win–loss record with a 4.14 earned run average and 78 strikeouts in his major league career. His most productive individual season came in 2023 with the Chicago White Sox, when he made 60 relief appearances and recorded 5 saves with a 3.39 ERA across 66 and one-third innings pitched. His MLB career has also included stints with the San Francisco Giants and Seattle Mariners, where he continued to serve in a bullpen role.
Other Wins and Performances
In the minor leagues, Santos posted several strong seasons, including a 2–0 record with a 0.89 ERA for the DSL Red Sox in 2017 and a combined 3–0 mark with a 1.29 ERA between the DSL Red Sox and DSL Giants later that same year. He was a Northwest League mid-season All Star in 2018 and an Arizona Fall League Rising Star in 2021, both honors that highlighted his prospect status. In 2026 with the Triple-A Sacramento River Cats, he posted a 2.45 ERA with three saves over eight appearances before being selected to the Giants’ major league roster.
Gregory Santos Family
Family Background and Racing Lineage
Gregory Santos is a native of the Dominican Republic, a country widely regarded as one of the strongest pipelines for professional baseball talent in the world. He signed with the Boston Red Sox as an international free agent in 2015, which marked the formal beginning of his career in organized baseball. Publicly available information regarding his parents or extended family is limited, and further details have not been confirmed.
Personal Life
Gregory Santos has maintained a relatively private personal life away from the field. His professional journey has taken him across multiple organizations, from Boston’s Dominican Summer League affiliate to the Chicago White Sox, Seattle Mariners, and back to the San Francisco Giants. Throughout his career, he has remained focused on his development as a relief pitcher and on returning to full health following the knee surgery that ended portions of his 2024 and 2025 seasons.
2025 Season Performance
Gregory Santos’s 2025 season with the Seattle Mariners was heavily disrupted by injury, as he appeared in only eight games and compiled a 1–1 record with a 5.14 ERA over seven innings pitched. His final outing came before April 25, 2025, when he was placed on the 15-day injured list due to right knee inflammation. The Mariners later announced that he would require cleanup surgery to repair cartilage, and he was transferred to the 60-day injured list on April 29.
On November 21, 2025, the Mariners non-tendered Santos, making him a free agent. Rather than remain in free agency for long, he signed a minor league contract with the San Francisco Giants on December 17, 2025, returning to a familiar organization. He was assigned to the Triple-A Sacramento River Cats to begin his preparation for a return to the major leagues.
Looking ahead, Santos opened his 2026 stint with Sacramento by recording a 2.45 ERA, six strikeouts, and three saves across eight appearances, demonstrating that his arm had recovered well following surgery. On April 29, 2026, the Giants selected his contract and added him to their active roster, signaling a renewed opportunity at the major league level. His return to the Giants organization, combined with a productive Triple-A stretch, sets a hopeful tone for his continued development as a high-velocity relief arm.
