The Black Cats boss has been playing Richardson in defence in recent games and feels he has excelled in that position.
Having already won eight England caps, Bruce believes Richardson can resurrect his international career if he makes his positional switch a permanent one.
"I think it is arguably his best position," he admitted. "I've seen him play there many times for Manchester United, even in the Champions League.
"I see him as a modern day full-back. He likes to get forward from deep and gives us attacking options.
Width"And he's always better when he is facing play and running on to defenders. In the two games he has played for us there he has looked very comfortable.
"If you look at the top teams like Chelsea, they get their width from their full-backs."
With England lacking a variety of options on the left flank, Bruce believes Richardson can force his way into Fabio Capello's World Cup plans.
"We haven't got that many natural left-sided players and if you play well you grasp the opportunity," he added.
"It's there for Keiran but I've got to look after Sunderland first."