The 38-year-old's current contract with the Red Devils runs out at the end of the season, and Ferguson says that it has not been decided if he will continue to play in 2013-14.
"There's not a time to make a judgement on [carrying on next year]," he told United's official website. "I think Paul will know himself.
"But he is still the best passer of the ball in the country. That's not stopped. He has still got the desire to play. He is 38 and Ryan is 39 on November 29.
"It's amazing, particularly with Scholesy, because he has had one or two injuries over the years and he quit last summer and then came back again."
Ferguson added that Scholes himself will decide on his future next summer.
"He made a fantastic contribution in the second half of last season," said the 70-year-old. "I just think he's doing what he's doing and he'll sort it out himself."
Scholes has won the Premier League 10 times and the Champions League twice with United.