 He was part of the squad that was promoted to League One as League Two runners-up after a 2–0 win at home to Aldershot Town on 27 April 2013, in which Mullins scored the opening goal.On 5 October 2012, Mullins joined League Two club Oxford United on a three-month emergency loan.He made his debut a day later in a 0–0 draw at home to Gillingham.