 After an injury to Nemanja Vidić, Cathcart was promoted to the first team squad as cover on 31 March 2007.He was an unused substitute in Manchester United's 7–1 win against Roma in the Champions League less than two weeks later, the FA Cup semi-final victory over Watford a further four days later, and the victory over Sheffield United on 17 April.Speculation that this defensive injury crisis would lead to Cathcart making his senior debut ended when he suffered a season-ending knee injury during training after the match against Sheffield United.