Scholes retired at the end of the last season aged 36, and United are playing a testimonial match for him on Friday night against the New York Cosmos at Old Trafford.
Ferguson said: "To my mind he will go down as one of the greatest players of all time for Manchester United.
"I was with Fabien Barthez on Wednesday having a chat and he said 'pass my regards on to Scholesy, he's the best player I ever played with'.
"You see [Barcelona's] Xavi talking about Scholes, and he's in a better position than most of us to talk about midfield players, saying he's the best player he has every played against."
Ferguson joked that notoriously publicity-shy Scholes would not enjoy being in the spotlight.
He added: "He might not turn up - if an interview is involved he won't, he will be quite happy with his slippers on!
"He will endure it - if he has to do an interview or something with the fans at the end of the game he will get through it somehow, but he will not be looking forward to it."