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I don't there is an equivalent in the NFL, because of how signing bonus money is treated. I don't think an NFL team can trade away cap liabililty on bonus money already paid out.
So if the Chargers sign Joey Bosa today, and trade him to the Saints tomorrow, the Chargers would assume all of Bosa's signing bonus money against their salary cap (I think it would be split between 2016 and 2017 since it's past June 1st, not positive).
If the Saints were to trade for Bosa, they'd have to trade for Bosa's draft rights first, then Loomis would commence to work on a deal with Bosa (still slotted as the #3 pick in the first round). The Saints would have to make painful cuts to take on a rookie contract that large.
Most of this is correct to my understanding. The deadline to trade for a players draft rights was August 8th, so that ship has sailed. Any bonus money already paid to a player accelerates onto the current years salary cap if that player is traded, if a player is cut as a post June 1st designee the hit is spread across two years. Bosa's contention is he wants all of his guaranteed bonus money in year 1. Time value of money says a dollar today is worth more than a dollar next year, so that is merely smart financial advice. $5M deferred to next year is worth $200k less than it is this year just using a simple 4% rate.
The important part of the above is "already paid" and Bosa wanting his money in the first year. What if, the Chargers were to sign Bosa and make his signing bonus payable in September. This would mean they would not have any out of pocket cash and Bosa could be signed and then traded to a team that would pay the entire signing bonus in September. New team assumes entire contract. I would think the Players Union would be for it as their player gets what he wants and I would think the Chargers would be for it at this point as the other option is he sits the year and they get nothing. Would the NFL front office poopoo it just because Goodell is a jerk?