Southern Illinois Miners Roark played one season with the
Southern Illinois Miners of the independent
Frontier League in 2008. In 3 games, he was 0–2 with a 21.41 ERA. In just 9.2 innings, he gave up 23 hits along with 25 runs while striking out 11.
Texas Rangers Roark was drafted by the
Texas Rangers in the 25th round of the
2008 MLB draft. He began his professional career with the rookie ball
AZL Rangers, and also appeared with the Single-A
Bakersfield Blaze. In 2009, Roark split the year between Bakersfield and the Double-A
Frisco RoughRiders, pitching to a cumulative 11-1 record and 3.02 ERA with 100 strikeouts. He was assigned to Frisco to begin the 2010 season.
Washington Nationals On July 31, 2010, he was traded, along with
Ryan Tatusko, to the
Washington Nationals in exchange for
Cristian Guzmán. In 2011, he was promoted to the Triple-A
Syracuse Chiefs, and posted, in 28 games (26 starts) an unremarkable 6–17 record, but he posted a 4.39 ERA with 7.9 strikeouts and 2.9 walks per nine innings. He began the 2012 season in Syracuse as a starter, then joined the bullpen for 20 relief appearances. Roark moved back to the rotation and had the best stretch of his career, allowing only 12 earned runs over innings in eight starts. against the
New York Mets in 2015 On August 6, 2013, Roark was called up to the MLB for the first time, and on the next day pitched two innings of scoreless relief, allowing only one hit. By the end of August he had appeared in nine games in relief, allowing earned runs only twice, and compiling an ERA of 1.19 over innings. On September 7, Roark made his first major league start against the
Miami Marlins, pitching six innings, allowing no runs and four hits, no walks, and four strikeouts, getting the win. Roark's dominance continued with a September 17 start against the rival
Atlanta Braves in which he pitched seven innings and allowed no runs on just three baserunners. His ERA dropped to 1.08 in innings. He finished 7–1 in 14 games (5 starts). On April 26, 2014, Roark threw his first career complete-game shutout (with a perfect game until the 6th), allowing only 3 hits in a 4–0 win over the
San Diego Padres. In 31 starts, Roark finished 15–10 with a 2.85 ERA in innings. In 2017, Roark went 13–11 despite posting a career-worst 4.67 ERA in 32 games (30 starts). On January 11, 2019, the Reds signed Roark to a one-year contract worth $10 million, avoiding arbitration. In 2019, Roark went 6–7 with a 4.24 ERA in 110.1 innings (21 starts) prior to being traded to the Oakland Athletics on July 31, 2019.
Oakland Athletics On July 31, 2019, the Reds traded Roark to the
Oakland Athletics for Jameson Hannah. In 2019, he allowed the highest line drive percentage of all major league pitchers (17.1%). He became a free agent following the season.
Toronto Blue Jays On December 18, 2019, Roark signed a two-year contract worth $24 million with the
Toronto Blue Jays. With the
2020 Toronto Blue Jays, Roark appeared in 11 games, compiling a 2–3 record with 6.80 ERA and 41 strikeouts in innings pitched. Roark pitched to a 6.43 ERA in three games for Toronto in 2021, allowing seven runs in as many innings, before being designated for assignment on April 30, 2021. On May 3, the Blue Jays released Roark.
Atlanta Braves On May 11, 2021, Roark signed a minor league contract with the
Atlanta Braves. On June 24, Roark was selected to the active roster. After posting a 2.14 ERA in 24 appearances (three starts) for the
Gwinnett Stripers, Roark elected free agency on September 5 when he was outrighted off of the 40-man roster. ==International career==