Darlow was responsible for the late Darren Fletcher winner, allowing the tame header to squirm past him, but Coloccini claims that the 25-year-old cannot be blamed for the defeat.
"When a player gets injured in the warm-up, or is sick like Robbie, and the team has to change it is always difficult," he told nufc.co.uk.
"But we cannot say that was why we lost. There is always a teammate who can come in and do the same work and today that was Karl.
"Karl is a very good goalkeeper, we trust him and have confidence in him. The result was not because of the change."