Richards has been left out of Fabio Capello's squad for the games against Slovakia and Ukraine after failing to establish himself in the Italian's plans.
The 20-year-old has not played for England since the 3-2 defeat to Croatia in November 2007 after bursting onto the international stage during that ill-fated European Championship qualifying campaign.
The versatile defender is part of Stuart Pearce's Under-21 squad for the double-header with Norway and France as he looks to catch the eye of Capello - and he believes he is beginning to recapture his best form.
"It does hurt when the England team get together," said Richards. "I played 11 games on the bounce for England and I thought I played well in all those games.
"I was a little unlucky to get an injury at the wrong time and then Wes Brown and Glen Johnson both came in and did a fine job and it has been hard for me to get back in.
"But my confidence is back again. I'm enjoying my football again at right-back and I feel like I'm knocking on the door."