Sweeney injured his groin in a training session and will be replaced by Blues player Nicky Robinson.
Speaking on Sweeney's injury coach Mike Ruddock commented, "We are terribly disappointed for Ceri, who is such a great player and popular member of the squad. We will know more about Ceri's injury on Monday, but the hope is that he will be back in contention next week."
TWEETS BY @DRAGONSRUGBY
