The 23-year-old now has the opportunity to impress another national team boss following this week's departure of Fabio Capello, who had been overlooking him. Richards has been behind Liverpool's Glen Johnson and Kyle Walker of Tottenham in the England pecking order despite his fine form for the Barclays Premier League leaders.
Mancini said: "Micah has everything to become a top full-back. I think he has improved a lot in the last year but he can still improve, he can do better. At this moment for the national team, probably Johnson or Walker are better. But I don't want to say Micah can't play for the national team - if he wants, Micah can play always."
He added: "If one England manager has a choice of three - Johnson, Walker, Micah - one of these players stays out.
"Micah played for England with Capello but there are a lot of players in England and one manager can call only 20-22 for a European Championship.
"I think Micah can really be a top full-back but he needs to improve."