The 37-year-old, who had made 466 league appearances for the Red Devils scoring 102 times, hung up his boots last summer to take up a coaching role at Old Trafford.
However, with the Red Devils short of central midfielders through injuries to Tom Cleverley, Anderson and Michael Carrick and Darren Fletcher sidelined with a chronic bowel condition, Scholes made a shock reappearance in the FA Cup Third Round tie against Manchester City on January 8.
Scholes, who has agreed to play until the end of the current campaign, marked his return to league action with the opening goal in United's 3-0 victory over Bolton Wanderers on Saturday.
And Ferguson, speaking to Yahoo!, revealed that the veteran pass-master came to him and admitted his regret at bringing the curtain down on his career prematurely.
He also explained his surprise that the news of Scholes' return for the cup clash at the Etihad Stadium was successfully kept a secret, with United's players not even aware of the plan.
"I don’t know how we managed it, we registered him on the Friday and we thought somehow it would get out," he said. "We left it as late as we possibly could; the game was a Sunday so we had the whole of Friday night, Saturday and Sunday morning to worry about it. But somehow we managed to keep it quiet and we did not let any of the players know.
"We did that because of the impact value. When the 5,000 fans in the away end knew he was on the team-sheet they were fantastic, the response was great. There were no negatives as far as I am concerned. He only stopped playing seven months ago and he has been training all the time with the reserves, coaching and training so his fitness levels have been decent.
"In the last few weeks he stepped it up to intensive training because when he came to see me he said: 'I think I have made a mistake, what do you think about me playing again?' There were no negatives. For me great, for the players in the dressing room great, and terrific for the fans.
"You’re getting a player for nothing who has been part of the club for 20 years. He knows the club. He is not going to play every game and Paul knows that, but in terms of composure and passing ability is there a better player going around? Definitely not."
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