 Donaldson made his Leeds Rhinos' début on 2 February 2019, in a 26-6 round 1 Super League defeat against the Warrington Wolves at the Halliwell Jones Stadium.Donaldson scored his first try for the Leeds Rhinos on 19 April 2019, in a 38-18 victory over the Huddersfield Giants.It was announced on 12 September.