Every team in the league has had multiple players do this. It’s a common work-around for the salary cap, and teams do it all the time.
Capology 101: NFL contracts are roughly 50% salary and 50% signing bonus. Salary is not guaranteed; if the team cuts you, you don’t see a dime of the remaining salary on your contract. Signing bonus is guaranteed, in that it’s paid in full immediately when you sign the contract. There are also “roster bonuses”, which are like a time-release signing bonus triggered at designated dates if the player is still on the roster.
One common technique in restructuring is to offer a long extension with a reasonable salary and a sizable signing bonus. This sizable bonus is money in hand, so the player is happy, and it only tangentally affects the cap, so the team is happy. Obviously you only want to go this route with players you are sure you want to keep, like Tom Brady. It is worth nothing that Peyton Manning restructured his mammoth contract last season.
Most NFL contracts involve escalating salaries. For example:
Signing bonus: $10 million
Year 1: $2 million (cap hit: 4m: 2m salary + 2m bonus)
Year 2: $3 million (cap hit: 5m: 3m salary + 2m bonus)
Year 3: $4 million (cap hit: 6m: 4m salary + 2m bonus)
Year 4: $6 million (cap hit: 8m: 6m salary + 2m bonus)
Year 5: $10 million (cap hit: 12m: 10m salary + 2m bonus)
This contract would be reported as a $35 million contract, which the agent gets to brag about when courting new clients. In reality, neither the player nor the team expect the last two years to be paid out. Instead, at the beginning of the fourth year, the team could offer the same basic contract as an extension, replacing the original contract. (Signing bonuses cannot be restructured; only salary can.) This would then work out as follows:
Signing bonus: $10 million
Year 1: $2 million (cap hit: 4m: 2m salary + 2m bonus)
Year 2: $3 million (cap hit: 5m: 3m salary + 2m bonus)
Year 3: $4 million (cap hit: 6m: 4m salary + 2m bonus)
Signing bonus: $10 million
Year 4: $2 million (cap hit: 6m: 2m salary + 2m original bonus + 2m new bonus)
Year 5: $3 million (cap hit: 7m: 3m salary + 2m original bonus + 2m new bonus)
Year 6: $4 million (cap hit: 8m: 4m salary + 2m original bonus + 2m new bonus)
Year 7: $6 million (cap hit: 10m: 6m salary + 2m original bonus + 2m new bonus)
Year 8: $10 million (cap hit: 14m: 10m salary + 2m original bonus + 2m new bonus)
So after the restructuring – during which the player just pocketed a cool $10 million for signing – the cap relief is significant. Year 4’s cap number dropped down from $8 million to $6 million, and year 5 dropped from the ridiculous $12 million to a more reasonable $7 million.
Another way to restructure is to move some of the salary over to incentives, but you have to bring the hard sell to go this route because it isn’t guaranteed. Incentives are also a bit more complex to figure in regards to the cap, since you enter the realm of Incentives Likely To Be Met (counts against the cap unless they fail) vs Incentives Not Likely To Be Met (doesn’t count against the cap unless they succeed), and the various criteria by which those categories are defined for any given incentive. Restructuring with incentives is usually a matter of “take this new deal or we’ll cut you.”