Oakland Athletics Overton was then drafted by the
Oakland Athletics in the second round of the
2013 Major League Baseball draft. After signing, Overton underwent
Tommy John surgery, a development which significantly lowered his signing bonus. He returned in 2014 and made his professional debut with the
Arizona League Athletics. He was later promoted to the
Vermont Lake Monsters, where he finished the season. Unfortunately, the surgery did affect his fastball velocity, which dropped from mid-90s to high-80s. Overton split the 2015 season with the High–A
Stockton Ports and the
Double-A Midland RockHounds. Overton began the 2016 season with an 8–4 record and 3.01
earned run average with the
Triple-A Nashville Sounds, before being promoted to the Athletics to make his major league debut on June 25, becoming the 11th Athletic to make a start during 2016. Overton made 5 starts with Oakland in 2016, going 1–3 with an 11.47 ERA, giving up 12 home runs in innings pitched. Following the signing of infielder
Adam Rosales, Overton was
designated for assignment on January 25, 2017.
Seattle Mariners On January 26, 2017, Overton was traded to the
Seattle Mariners in exchange for minor-leaguer Jason Goldstein, adding to Seattle's starting pitching depth. Overton pitched to a 6.31 ERA for Seattle and was designated for assignment.
San Diego Padres On June 19, 2017, Overton was claimed off waivers by the
San Diego Padres. He made one start for the Padres before he was removed from the 40–man roster and sent outright to the Triple–A
El Paso Chihuahuas on August 31. In 2018, Overton played for the rookie–level
Arizona League Padres, Double–A
San Antonio Missions, and El Paso. In 25 games (14 starts) for the three affiliates, he compiled an 8–2 record and 2.90 ERA with 72 strikeouts over innings pitched. Overton made 25 appearances (22 starts) for El Paso in 2019, registering a 10–5 record and 5.46 ERA with 103 strikeouts across innings pitched. He elected free agency following the season on November 4, 2019.
Arizona Diamondbacks On March 11, 2020, Overton signed a minor league contract with the
Arizona Diamondbacks. He did not play in a game in 2020 due to the cancellation of the minor league season because of the
COVID-19 pandemic. Overton was released by the Diamondbacks organization on May 22.
Rakuten Monkeys On December 21, 2020, the
Rakuten Monkeys of the
Chinese Professional Baseball League signed Overton for the 2021 season.
Colorado Rockies On February 18, 2022, Overton signed a minor league contract with the
Colorado Rockies. In 12 games (11 starts) for the Triple–A
Albuquerque Isotopes, he struggled to a 2–7 record and 8.60 ERA with 39 strikeouts in 45.0 innings of work. On July 8, Overton retired from professional baseball. ==Personal life==