McCormack made his first appearance of the 2016–17 season in a 1–0 defeat to League Two team Exeter City in the EFL Cup first round on 9 August 2016, in which he was substituted in the 12th minute after suffering a foot injury. He returned to the team seven weeks later, but made just three appearances before being handed a five-match suspension and a £6,000 fine on 20 October, for charges relating to the use of "abusive and/or insulting words towards a match official" during a match against Cardiff City on 19 April 2016. After his return from suspension, he made just eight substitute appearances, making his final appearance as a substitute for Konstantin Kerschbaumer in the final match of the season, a 3–1 defeat to Blackburn Rovers. McCormack was released at the end of the season and finished his Brentford career with 104 appearances and three goals.