Rodgers and Matthews (possibly Woodson) are the only players we've had that I think scored big contracts with bonus money exceeding 15 million or was significantly more than 25% of contract. I don't recall the specifics of Peppers contract so I could be wrong by not including him.
The fact is, we have been exempt up to now imo. Take a look at some of the crazy contracts with huge bonuses being signed out there. Moreover, the die has been cast as to how management structures contracts. Shields, Nelson, Cobb and Bulaga are under very similar contracts. Only the very best are getting big bonuses here.
Based on $15 million in signing bonuses under current contracts, you would be correct. That's Rodgers and Matthews only. However, you can't compare contracts from just a couple of years ago to recent ones under the escalating cap.
For example, Burnett's contract is the second richest in per year total value (Chancellor is first) and the highest in guarantees among safety contracts signed in 2013 or prior that are still on the books. At the time, the contract was surprisingly rich with a Pro Bowl-level projection embedded in it.
Or consider the deal Hawk signed after the 2010 season. That was a Pro Bowl-level contract as well, with a signing bonus creating sufficient dead cap to make his replacement prohibitive despite a steep decline evidenced by 2012. It was not until the dead cap was manageable for 2015 that we saw his departure. While Brad Jones' deal was not among the richest in the league, dead cap played into the timing of his release past the sell-by date.
The only 2015 Packer 2015 big dollar contract is Mike Daniels. Compare and contrast his deal with the recent deals for non-Pro Bowl peers. It is not cheap in terms of total value or signing bonus:
http://overthecap.com/position/3-4-defensive-end/
There are a couple of levels to look at in terms of risk in a contract. Signing bonus is one, in terms of the deferred liability, but that's just one element to consider. We often hear that total guarantees are representative of risk. While this true, there are other important considerations. The players who get big guarantees are not typically the kinds of players who drop out of the l league from injury. Even if ability is diminished, they're typically still good enough to play. It's the marginal players who do regularly do not survive in the league after diminishment of ability.
The real measure of a contract is the dead cap and cap savings and the year at which the amount ceases to be prohibitive in considering a players release in the event of performance decline by injury or otherwise.
Let's take Daniels' contract as an example since it was signed under the current salary cap level, with a singing bonus in line with peers:
http://overthecap.com/player/mike-daniels/1126/
Let's say he blew his ACL tomorrow. Are you going to cut him? Of course not. Why? Besides the fact he's a good young player with a good chance to maintain at least starter level performance upon return, you'd incur $13.4 million in dead cap and a $6 mil cap loss in 2015. With cap space currently at $8.5 mil for the top 51, you'd take cap space down to near zero when cutting him even if he broke his neck, which is out of the question going into the season. It could drive cap under zero depending on the IR body count and the cost of replacements entering the season.
Let's say instead he blew his ACL at this time next year. Or lets say his performance simply declined after getting the big contract. Would you cut him then? Well, the cap savings would be only $3.2 million. It would take a precipitous decline to even consider it since the question would be, "can you replace him with equivalent performance on a 1 year, $3.2 million contract". That's a very low bar. And when you consider that one of the Packers' more obvious elements of cap philosophy is "no meaningful dead cap!" the bar goes lower. This Packer philosophy, together will reluctance to seek replacements in the free agent market, may factor into an agent's view toward taking less signing bonus in exchange for other considerations.
It isn't until 2018 where injury or decline comes into play where the cap savings is $5.1 mil. Then again, the dead cap is $4,8 million, the kind of amounts the Packers avoid incurring like the plague.
Add it all up, and the practical affect given dead cap/cap savings under Packer philosophy is that Daniels' signing bonus, 2016 and 2017 salaries, and the roster bonuses for those seasons are effectively guaranteed short of an actual career ending, but not a career-threatening, injury: $24 million. He's certainly a good player, a core player, but some measure of his value is the relative weakness of the positions group, or what I refer to as "who else ya got?"
Now consider why the Packers might be pressed against the salary cap with a big crop of key free agents hitting the market next season. Whether you look at Cobb, Nelson, Shields, Bulaga or Daniels, or even Matthews high ticket contract, the cap numbers escalate year by year through the contract. Consider the 2017 cap numbers, dead cap and cap savings in those high ticket contracts even without the $15+ mil signing bonuses:
http://overthecap.com/salary-cap/green-bay-packers/
Even if you don't expect performance up to the cap number when the time comes, the players will be kept so long as expected performance exceeds the cap savings. And it seems with cases in the past, the dead cap has been the determining factor in what may be regarded as wishful thinking.