There’s really not a lot to negotiate any more. Hutch’s contract was pretty much set in stone. The two things that I’m aware of that they can negotiate is whether the signing bonus is paid all at once or if it’s split in two payments (Sewell got half at signing, the other half at the start of training camp). And whether the cash paid is in base salary of a roster bonus (he’d get it earlier if it was a roster bonus). But all pretty minor.
You get into the 2nd and 3rd round picks and you negotiate offsets (if draft pick is a bust, he gets to collect some or all of his rookie contract plus collect on a new contract with new team).
Later round picks, there are no guarantees other than signing bonuses and no offsets, you just negotiate the amount of the signing bonus. The full amount of signing bonuses are paid at signing.
That’s most of the stuff, there are other stuff, but most of the rest has to do with injuries.
I remember that Joey Bosa had a contract holdout with the Chargers because he didn’t like the terms of his signing bonus. The total value was set by the wage scale, but Bosa wanted more of his money sooner.
It didn’t have to do with the amount, it had to do with the timing of the payment. Chargers wanted to defer paying the majority of the signing bonus until the next season. Joey/agent wanted the bonus paid in 2016.