England play host to their oldest international rivals on 14 August, in a match to mark the 150th anniversary of the FA.
The FA had been confident the match would sell out, but there are around 10,000 tickets unsold.
And the governing body is refusing to release the tickets on general sale to prevent Scotland fans from buying seats in the home end of the ground.
The FA is adamant they have made the correct call though, and will not buckle to pressure on the issue.
"I don't think we should be ashamed of that and suddenly change a ticketing strategy to sell a remaining 6,000-7,000 if that is still the case by this time next week," a spokesman for the FA said in the Daily Telegraph.
"The benefits don't outweigh the benefits of keeping it among a closed group for both our fans and Scotland fans.
"Is it enough of a benefit to have them sold and not know who is buying them?"