The Norfolk-born 18-year-old helped the Under-18s reach the quarter-finals of the FA Youth Cup last season and clinch the runners-up place in their league.
Rudd, an England Under-19 international, has had one taste of first-team experience having been named on the bench for the final game of the 2007/08 season against Sheffield Wednesday.
Manager Bryan Gunn told the club's official website: "This is a big season for Declan off the back of a tremendous campaign last year for the Academy and a few reserve appearances.
"He now has an opportunity to really make a name in the professional game and has the attributes and the capability of being a top goalkeeper. We have to nurture him the best way we can with his education and training.
"He has been recognised at England level and is now playing above his age group and we are delighted to have signed him."