However, Mourinho insists that he is merely resting Mata following a busy summer for the 25-year-old.
"There is no chance Juan goes," the Portuguese is quoted as saying by Goal.com. "He had a very small pre-season after the Confederations Cup, and during that pre-season he was injured. He started training two days before we played the first league match."
Mata joined Chelsea from Valencia in summer 2011 for £23.5m.