United and Madrid in August agreed a £29million transfer that would have seen the goalkeeper swap Old Trafford for the Bernabeu, but the proposed switch fell through after the requisite paperwork was not submitted before the Spanish deadline.
On Monday, Football Leaks website published a document it claims is the contract De Gea was due to sign at Madrid.
It shows the Spain international would have received a figure of 11,818,182 euros (£9.2million) for each season from 2015-16 to 2020-21.
There is also mention of a break clause of 500million euros (£388million), which De Gea would have been obliged to pay if he walked out on his contract.
Only a few days after the move failed to materialise, United announced De Gea - who joined them from Atletico Madrid on a five-year deal in 2011 - had signed a new four-year contract, with an option to extend for a further year.
That deal was reportedly worth £200,000 per week
The figures from the Football Leaks document equate to around £176,000 per week.
Source: PA