Ragans underwent Tommy John surgery in March 2018 and missed all of the 2018 season.[9] On May 14, 2019, the Rangers announced that Ragans had suffered a tear in the graft of his surgically repaired left elbow during his rehabilitation process. The tear resulted in a second Tommy John procedure which resulted in him missing the entire 2019 season.[10] Ragans did not play in 2020 due to the cancellation of the Minor League Baseball season because of the COVID-19 pandemic. Ragans opened the 2021 season with the Hickory Crawdads of the High-A East.[11] In June 2021, Ragans was selected to play in the All-Star Futures Game.[12][13] Ragans was promoted to the Frisco RoughRiders of the Double-A Central on July 18, after going 1–2 with a 3.25 ERA and 54 strikeouts over 44+1⁄3 innings for Hickory.[14] He finished 2021 after posting a 3–1 record with a 5.70 ERA and 33 strikeouts over 36+1⁄3 innings for Frisco. Ragans returned to Frisco to open the 2022 season, going 5–3 with a 2.81 ERA and 65 strikeouts over 51+1⁄3 innings, before being promoted to the Round Rock Express of the Triple-APacific Coast League on June 14.[15] Over 8 starts for Round Rock, Ragans went 3–2 with a 3.32 ERA and 48 strikeouts over 43+1⁄3 innings.[16] He was named the Texas Rangers 2022 Nolan Ryan Pitcher of the Year.[17]
On August 4, 2022, Texas selected Ragans' contract and promoted him to the active roster for the first time.[18][19] In his MLB debut that night versus the Chicago White Sox, Ragans allowed one unearned run over five innings while recording three strikeouts.[20] Over 9 game for Texas, Ragans went 0–3 with a 4.96 ERA and 27 strikeouts over 40 innings in 2022.[21] He went 2-3 with a 5.92 ERA in 17 appearances with the Rangers in 2023.
Kansas City Royals
On June 30, 2023, the Rangers traded Ragans and minor league outfielder Roni Cabrera to the Kansas City Royals in exchange for Aroldis Chapman.[22] After joining the Royals and moving from the bullpen, where he had made all of his 2023 appearances with Texas, to the starting rotation, Ragans saw increased success across his first 47 innings with Kansas City.[23] He received the AL Pitcher of the Month Award for his performance in the month of August.