Isaac Mattson Overview
Isaac Gerald Mattson is an American professional baseball pitcher for the Pittsburgh Pirates of Major League Baseball (MLB). A right-handed pitcher drafted in 2017 by the Los Angeles Angels, Mattson has played for multiple MLB organizations including the Baltimore Orioles and Pittsburgh Pirates, as well as several minor league teams. Known for his consistent performance in relief pitching roles, Mattson has demonstrated steady improvement throughout his professional career.
Early Life and Amateur Career
Isaac Gerald Mattson was born on July 14, 1995, in Harborcreek, Pennsylvania, to parents Edward and Debra. He attended Harbor Creek High School where he excelled in both baseball and basketball. In his senior year of 2014, he achieved an impressive 6-0 record with a 0.67 ERA while also batting .531. Despite these achievements, Mattson was not drafted in the 2014 MLB draft and enrolled at the University of Pittsburgh to continue his baseball career.
During his college career at Pitt, Mattson developed into a reliable pitcher. As a freshman in 2015, he appeared in 22 games, going 1-1 with a 3.82 ERA. His sophomore season in 2016 saw him pitch 34 innings in relief, compiling a 2-0 record with a 3.71 ERA. Following his sophomore year, Mattson played for the Chatham Anglers of the Cape Cod Baseball League where he was named an all-star. As a junior in 2017, he pitched 31 innings out of the bullpen, going 1-0 with a 2.87 ERA while striking out 41 batters.
Professional Career Beginnings
After his junior season at Pittsburgh, Mattson was selected by the Los Angeles Angels in the 19th round of the 2017 MLB draft. He made his professional debut with the Arizona League Angels before being promoted to the Orem Owlz, where he was named an All-Star. In 31 1/3 innings between the two clubs, he went 1-0 with a 1.44 ERA. In 2018, Mattson played for the Burlington Bees and Inland Empire 66ers, going 7-4 with a 3.82 ERA in 25 games (11 starts). The following year, he began with the 66ers before being promoted to the Mobile BayBears in May, and then to the Salt Lake Bees in August. Over 37 relief appearances between the three clubs, Mattson went 6-3 with a 2.33 ERA, striking out 110 over 73 1/3 innings.
Isaac Mattson Professional Journey
Isaac Mattson has progressed through multiple levels of professional baseball since being drafted in 2017, developing from a promising rookie into a consistent MLB pitcher. His career has included stops with several organizations, demonstrating resilience and adaptability across different league environments.
Early Minor League Development (2017-2019)
During his first three professional seasons with the Los Angeles Angels organization, Mattson steadily improved his performance metrics. After a strong debut in 2017 with a 1.44 ERA, he maintained a sub-4.00 ERA across multiple levels in 2018 and 2019. His performance earned him a selection to the Arizona Fall League for the Mesa Solar Sox following the 2019 season. By the end of 2019, he had established himself as a reliable relief pitcher with strikeout potential, having recorded 110 strikeouts in 73 1/3 innings across Double-A and Triple-A levels.
The late-2019 trade to the Baltimore Orioles marked a significant transition in Mattson’s career, as he was acquired alongside three other pitchers in exchange for Dylan Bundy. Although the 2020 minor league season was cancelled due to the COVID-19 pandemic, Mattson was added to the Orioles’ 40-man roster in November 2020, positioning him for his first opportunity at the MLB level.
MLB Debut and Early MLB Experience (2021-2022)
On May 7, 2021, Mattson made his MLB debut with the Baltimore Orioles, pitching 2/3 of an inning and allowing one run. He recorded his first career strikeout on July 3 against David Fletcher of the Los Angeles Angels. However, his performance in the majors was inconsistent during his brief MLB appearance, posting a 6.23 ERA with just 3 strikeouts in 4 appearances. After being outrighted to Triple-A Norfolk in April 2022, Mattson was released by the Orioles organization on July 18 of that year.
The remainder of 2022 saw Mattson playing in independent baseball leagues. He signed with the Washington Wild Things of the Frontier League in August, where he recorded a 2.40 ERA with 23 strikeouts in 15 innings across 12 appearances. This performance kept him active in professional baseball despite being released from MLB-affiliated organizations.
Independent League and Return Affiliation (2023)
In 2023, Mattson continued his journey through independent baseball, signing with the Southern Maryland Blue Crabs of the Atlantic League in March. With the Blue Crabs, he appeared in 18 games, logging a 3.32 ERA with 24 strikeouts and 3 saves in 19 innings pitched. His performance earned him another opportunity in affiliated baseball when he signed a minor league contract with the Minnesota Twins organization on June 22, 2023.
With the Double-A Wichita Wind Surge, Mattson demonstrated improved performance, registering a 3.62 ERA with 42 strikeouts across 32 1/3 innings in 21 appearances. This solid showing earned him another opportunity to return to affiliated baseball, though he would become a free agent following the season on November 6.
Pittsburgh Pirates Era (2024-Present)
On December 11, 2023, Mattson signed a minor league contract with the Pittsburgh Pirates. He began 2024 with Double-A Altoona before being promoted to Triple-A Indianapolis, where he compiled a 7-2 record and 3.17 ERA with 89 strikeouts over 37 games. The Pirates selected his contract on September 19, 2024, adding him to their active roster. In his first MLB appearances with Pittsburgh, he posted a 5.06 ERA with 6 strikeouts over 5 1/3 innings. Following the season, he was removed from the 40-man roster and elected free agency on November 4, 2024.
Mattson quickly returned to the Pirates organization, re-signing on a minor league contract on November 18, 2024. In 2025, he began with Indianapolis, posting a 2.50 ERA with 22 strikeouts and 4 saves in his first 16 outings. His performance earned him his second MLB promotion on May 20, 2025. On June 7, Mattson earned his first career MLB win after tossing a scoreless seventh inning against the Philadelphia Phillies. By season’s end, he made 44 relief appearances for the Pirates, going 3-3 with a 2.45 ERA and 45 strikeouts over 47 2/3 innings.
Personal Life
Isaac Mattson was born to parents Edward and Debra and was raised with seven siblings. His mother, Debra, died by suicide in July 2021. He married his wife, Devin, in November 2022, and their first child was born in February 2025. Despite personal challenges, Mattson has maintained his focus on baseball, demonstrating resilience throughout his professional career.
Isaac Mattson Career Statistics and Achievements
Isaac Mattson has developed into a reliable relief pitcher during his professional baseball career, marked by consistent improvement and adaptability across multiple organizations. His performance has shown particular strength in strikeout ability and run prevention, particularly during his time with the Pittsburgh Pirates.
MLB Performance (2021-Present)
In Major League Baseball, Mattson has primarily appeared in relief roles for the Baltimore Orioles (2021) and Pittsburgh Pirates (2024-Present). Through June 30, 2026, he has accumulated a 3-3 record with a 3.14 ERA and 76 strikeouts across multiple MLB seasons. His most significant MLB performance came during the 2025 season with the Pirates, when he achieved a 2.45 ERA with 45 strikeouts in 44 appearances. His first career MLB win on June 7, 2025, marked an important milestone in his development as a major league pitcher.
Minor League and Independent Career
Throughout his minor league and independent league career, Mattson has demonstrated consistent performance across multiple levels of professional baseball. His career highlights include being named an All-Star in the Arizona League (2017) and Cape Cod Baseball League (2016). In 2019, while pitching for three different Angels affiliates, he achieved a 2.33 ERA with 110 strikeouts in 73 1/3 innings. His independent league performance with the Washington Wild Things (2.40 ERA in 2022) and Southern Maryland Blue Crabs (3.32 ERA in 2023) kept him active and prepared him for his eventual return to affiliated baseball.
Pittsburgh Pirates Era Highlights
Since joining the Pirates organization, Mattson has shown significant development as a pitcher. In 2025, he established himself as a reliable reliever with a 2.45 ERA and maintained a strikeout rate that demonstrated his ability to miss bats at the major league level. His performance during the 2025 season, including his first MLB win and consistent appearances out of the bullpen, positioned him as an important piece of Pittsburgh’s relief corps for future seasons.
Amateur Career Achievements
During his amateur career, Mattson achieved notable success both in high school and college. At Harbor Creek High School, he went 6-0 with a 0.67 ERA in his senior year while also batting .531. In college at the University of Pittsburgh, he earned All-Star honors in the Cape Cod Baseball League following his sophomore season. His junior year performance at Pitt (1-0 record with 2.87 ERA and 41 strikeouts in 31 innings) contributed to his selection in the 19th round of the 2017 MLB draft.