 He made his Yeovil debut on 30 August, in a 4–3 victory over Portsmouth in an EFL Trophy fixture at Huish Park.On 14 April 2017, following an injury to first-choice keeper Artur Krysiak, Maddison made his English Football League debut for Yeovil at Newport County.In June 2017, after making 11 appearances in his first season with the "Glovers", Maddison signed a new two-year contract with the club.