I'm not advocating for a big WR trade. It's most likely not happening.
However, I just want to point out that the fine folks at WGR asked Sal C about the hypothetical and trading for a guy like Deebo or Aiyuk. They asked him if the base salary that transfers to the Bills immediately after the trade needs to fit under the Bills cap BEFORE they right away restructure the deal to lower the first year initial cap hit. Sal's answer was No, they don't need to. They can basically have the restructure set and ready to go as soon as the trade is finalized. So the argument that the Bills would need to have 14+ million in free cap space to land Aiyuk (Or Deebo) before they restructure is not a hurdle to land them. They can have only say, 10 Mill, and when his 14.2 or whatever it is moves to the Bills, they can restructure at the same time, and lower it to say 7 Million and will stay cap compliant.
Now, I will say, Sal wasn't reading straight from the CBA. But he said there is leeway there from the league to make the trade and restructure Right Away.
Again, Not Advocating. Just passing along what Sal said as they don't have the room to do that, and leave room for injury replacement and the rookie deals, etc, etc.