[11] In 7 starts for the Double–A New Britain Rock Cats, he compiled a 1–4 record and 5.40 ERA with 31 strikeouts over 41+2⁄3 innings pitched.

Marshall signed with the Sugar Land Skeeters of the Atlantic League of Professional Baseball for the 2015 season.

On June 23, 2016, Marshall signed with the Sugar Land Skeeters of the Atlantic League of Professional Baseball.

On June 20, 2018, Marshall signed with the Southern Maryland Blue Crabs of the Atlantic League of Professional Baseball.

On August 31, 2018, Marshall was traded to the Long Island Ducks of the Atlantic League of Professional Baseball.