Palace's negotiating position has been weakened by the absence of bids to challenge United's opening offer, which is understood to be around £5million with £5m add-ons. The low offer for a player Palace would expect to command at least £12m for has left them acutely aware that there would be discontent from their fans if they accept.
Asked last night if a price had been agreed, Palace chairman Steve Parish said: "I'm not going to answer."
But his comments point to a loan-back deal, as Parish did make an unequivocal pledge to his club's fans that Zaha would be playing for Palace through until the end of the season.
"Right now, he's a Crystal Palace player and he'll be a Crystal Palace player in the summer. That's the only thing I can tell you," Parish said.
"He'll definitely be playing for us until the end of May whatever happens. I've said it countless times -- there's no way the player is going to leave the club in January. That's where we are and that's where we've always been with it."
It is unclear whether Ferguson met Zaha in London on Sunday night, after United's game at Tottenham. Ferguson is known to be attending a Manchester United Foundation round-table dinner while his players are away.
The English Football Association yesterday contacted Ferguson asking him to explain the comments he made to the media about referee's assistant Simon Beck.
Ferguson is unlikely to face punishment for his comments about the linesman who did not spot a penalty-box infringement on Wayne Rooney at White Hart Lane -- despite West Ham manager Sam Allardyce being charged for his comments at Old Trafford last week.
While Allardyce made a clear reference to the referee favouring United in the FA Cup third-round replay by suggesting he gave decisions based on who was the home team, Ferguson said the linesman had a bad game and they had suffered against him in the past. If he had said, "he always gives decisions against us", then he would have been punished. He just about stayed on the safe side of the line.
Meanwhile, Ferguson is understood to be on the lookout for a replacement for David de Gea after the Spanish goalkeeper gave another weak display under the high ball at Spurs on Sunday.
Ferguson has become exasperated by De Gea's inability to iron out the flaws in his game and senior players at the club are understood to have lost faith in the 22-year-old, even before his costly injury-time mistake against Tottenham.
Concerns over the reliability of Anders Lindegaard, brought to a head by an alarming performance during a 4-3 victory at Reading last month, have presented Ferguson with a problem, however, in terms of his goalkeeping options for the rest of this season.
With United still pursuing three trophies, De Gea is likely to be selected ahead of Lindegaard, a Denmark international, for the club's key fixtures on the grounds of his greater shot-stopping abilities.
The club have recently scouted Stoke City stopper Asmir Begovic and Galatasaray's Uruguay international Fernando Muslera, with no leading candidate emerging to replace De Gea.
Elsewhere, Rio Ferdinand admits United got a taste of their own medicine at Tottenham, but the defender insists the team should not be disheartened at coming away from White Hart Lane with a point, after Clint Dempsey's 93rd-minute equaliser.
"It is disappointing," Ferdinand said. "But as soon as you get off the pitch and into the changing room you think back to how many times we have done that to other teams over the years and you have to accept it and take it on the chin."