The hold up may be caused by United’s policy regarding Champions League qualification.
Wages are automatically reduced by 25 per cent if they fail to finish in top four, or win the Europa League.
That would mean De Gea’s wages would drop from £350,000-a-week to £263,000-a-week.
If he were to sign for another club, he could make sure his wages stayed the same throughout the entire period he’s there.
If the contract still hasn’t been signed by January, De Gea will be free to speak to other clubs, and could even sign a pre-contract deal.
Without a transfer fee, there would be a major spike in his wages, and the goalkeeper may decide to gamble on leaving United in a bid to secure a bigger deal elsewhere.
Real Madrid have long been linked with a move for De Gea, and may be tempted to sign him next summer.
He almost moved to the Bernabeu on transfer deadline day in 2015, but the deal never happened because of a problem with a fax machine, and the documents weren’t signed ahead of the deadline.
PSG are still looking for a new long-term goalkeeper, and De Gea could be the ideal target.
There have been talks with Real Madrid over signing Thibaut Courtois as part of a swap deal for Neymar, but that’s yet to be agreed.
Meanwhile, De Gea will be looking to improve his form for United after a nightmare end to last season.
United’s next match will be against Crystal Palace in the Premier League on Saturday (3pm), at Old Trafford.