Marklund did not play in a game in 2020 due to the cancellation of the minor league season because of the COVID-19 pandemic.[6] He underwent Tommy John surgery in April 2021 and missed the entirety of the season as a result.[7] He missed the entire 2022 campaign as well, and was released by the Royals organization on April 25, 2023.[8]
Winnipeg Goldeyes
On April 27, 2023, Marklund signed with the Winnipeg Goldeyes of the American Association of Professional Baseball.[9] In 12 games for the Goldeyes, he struggled to a 15.53 ERA with 9 strikeouts across 13+1⁄3 innings of work. Marklund was released by the Goldeyes on July 9.
Québec Capitales
On May 9, 2024, Marklund signed with the Québec Capitales of the Frontier League.[10] He made 6 appearances out of the bullpen, registering a 2.70 ERA with 10 strikeouts over 6+2⁄3 innings. On June 1, Marklund was released by the Capitales.[11]