Moyes was charged with repairing the relationship between club and player but instead plunged the England striker's future into further doubt when he suggested Rooney would be mere back-up to Robin van Persie.
Souness remarked: "Whether it was intentional or unwise words by David Moyes, if I'm Wayne Rooney I'm thinking 'hang on, I'm the star of the show'.
"He sees himself as now second fiddle to van Persie. He will be a very unhappy young man at that - his ego's been dented.
"Manchester United have put themselves in very difficult situation, but I don't think they can sell him to an English team."