 He started for Seattle in Soccer Bowl '82 before being substituted for Roger Davies, and the match was won 1–0 by the New York Cosmos with a 31st-minute goal scored by Giorgio Chinaglia.Less than a month later he made a temporary return to England by signing for Forest's local rivals Derby County on loan on 13 October 1982.Mills made his debut three days later in a 1–1 away draw with Grimsby Town in the Second Division, before scoring his first goal with Derby's second in a 2–0 home win over Queens Park Rangers on 3 January 1983.