Rooney interview with ESPN
United have enjoyed a successful summer in the transfer market after bringing in David de Gea, Phil Jones and Ashley Young, but they are yet to find a like-for-like replacement for Scholes following his retirement at the end of the season.
Scholes himself has suggested that Rooney - who excelled in a more withdrawn role last season - could eventually become a midfielder, but Ferguson has dismissed that suggestion.
"Scholesy is being very generous there," he said. "He's underestimating himself and the value he had to us. Wayne could play centre-midfield, but not the way that Scholesy played it. They're too different.
"The way Wayne would play as opposed to Scholesy is that he would be more dynamic and all over the place, using his energy to run everywhere, challenge and hit those cross-field passes that he's terrific at.
"Scholes was more calculated. He always had that control about him, controlling the speed and pace of a game, which is pretty difficult to do. He was an absolute one-off.
"You can't replace players like that. You hope you can get something approaching it, but you'll never replace Scholes. We're all searching for that. Everybody is searching for the special player who makes the difference to his team."
Many believe Inter star Sneijder would be a fine replacement for Scholes, but Ferguson continues to deny a move is in the offing.
"There's nothing on the horizon at the moment, so we carry on with the players we've got," he said. "I'm not going to talk about that. It's not an issue. It's just difficult.
"We lost five experienced players in the summer. Five players who gave the club great service - Wes Brown, John O'Shea, Edwin van der Sar, Paul Scholes, Gary Neville. At the time, you think it's a big slice out of the cake, but we have replaced them by adding De Gea, Jones and Young, and also bringing back Danny Welbeck and Tom Cleverley, who were on loan.
"We've actually got 12 players aged 22 or under with us now, so it could be an emerging team again. There are also some experienced players who are maturing and will carry the responsibility of performance - Nemanja Vidic, Patrice Evra and Rio Ferdinand have responsible roles, as do Ryan Giggs, Michael Carrick and Michael Owen.
"These are experienced players we've got, and the young players will be desperate to get in their positions, so I think it's a healthy situation we're in."