Former Celtic striker and now a popular football pundit, Chris Sutton has heavily criticised Dedryck Boyata on social networking site Twitter.
The Scottish Sun reported this week that the former Manchester City defender refused to train with the Celtic squad ahead of their match against Hearts, and fresh reports from the same publication has emerged that he has not travelled with the rest of the squad to Greece for their Champions League qualifier against AEK Athens.
The Belgian international was heavily linked with a move away from Celtic this summer.