 By the time his goal tally had reached 77 for Doncaster he had attracted the attentions of bigger clubs and on 1 March 1978 Stoke City manager Alan Durban signed him for £40,000.The following Wednesday O'Callaghan was on the bench as Stoke struggled to break down a resolute Hull City and with time running out and Stoke winning a corner Durban decided to bring O'Callaghan on for his début.From the resulting corner he headed past Eddie Blackburn to make him an instant hero (fastest debut goal).