They are pro-rating all these signing bonuses over the length of the contracts. I think they can do it for five years under the new CBA. So if you give a 10 mil signing bonus, it only counts for 2 million against this year's cap. Basically they are re-doing the contracts of the free-agents they signed a few years ago, to make more cap room now, it will eventually lead to a load of "dead money" against their cap in a few years.
Sooner or more likely later, they will have to pay the piper. If they didn't get a new CBA the Redskins would have been decimated this year, sooner or later, that is going to happen.