There’s something strange brewing in Oakland between new head coach Jon Gruden and All Pro edge defender Khalil Mack. Mack has been holding out of training camp, hoping to sign a bigger deal than the rookie fifth-year option he’s currently on, which is netting him $13.8 million. If the Raiders can’t come to a long-term deal, Mack could be a free agent next year.

So in response to this critical decision, Gruden has apparently said... nothing. There’s a report out there that Gruden hasn’t even spoken to Mack since February. To make matters even more tense, Gruden said this in a press conference this week:

“We weren’t very good last year on defense with Khalil Mack. We didn’t have an interception, I think, all year. I don’t know if we intercepted a pass until Week 14. We’ve got to get a better pass rush, we’ve got to play better defense, period. And we hope Khalil gets here, but in the time being, we’ve got plenty of guys who need work.”

So, naturally, trade rumors have been starting to bubble up. While it’s almost certain that the Raiders would never trade a top five defender in the NFL this late in the season, some analysts think it could happen. In fact, former Washington general manager Vinny Cerrato said on a radio interview that, “My gut tells me that they’ll trade him and try to get some good draft picks for him.”

While I believe this is still extremely unlikely, let’s go down this rabbit hole for a minute. The Lions have a glaring need at defensive end, and the guy they’re clearly leaning on for 2018 remains on the Physically Unable to Perform list for the second straight training camp.

Mack would be an absolute game-changer, not just for the Lions, but for any other team in the NFL. The man has 36.5 sacks in the past three years, and hasn’t finished a season with less than 73 tackles.

There’s little doubt the Lions would be interested in a guy like Mack, but acquiring him would undoubtedly cost a lot, both in terms of compensation for the Raiders and cap room for Mack. Here’s a look at what something like that would cost:

Compensation for the Raiders

It’s hard to draw on any precedent here because trading a premier pass rusher in the prime of their NFL career just does not happen... ever. Consistent pass rushers are so valuable and so rare that you don’t often see them hit free agency, let alone get traded.

So what would it take for the Raiders to be comfortable letting Mack go? Well, any time there’s a big-name trade like this, two first-round picks is always a good starting point. It’s what the Giants were reportedly asking for in return for Odell Beckham Jr. When Washington traded up in the draft to get Robert Griffin III, they sent away their next two year’s first-round picks (plus a second-round pick).

Would that be enough for Chucky to pull the trigger? It’s almost impossible to know, but that’s probably where conversations would begin.

The Lions could also offer players in return. Seeing as Oakland would need a pass rusher in return, Ezekiel Ansah could be part of the deal. However, Ansah’s injury and inconsistency would make it so it’s not even close to a fair one-to-one trade. The Lions would have to sweeten the deal with another key player.

Looking at the Raiders’ roster, the team could certainly use some depth in the secondary—something the Lions seem to have in spades. Throw in Nevin Lawson, Teez Tabor or DeShawn Shead, and we may be getting closer to an even deal.

But even that is likely not enough. We’re talking about one of the best defensive players in the NFL, so an unreliable pass rusher and a CB2 isn’t going to be enough. The Lions would like have to throw a first-round draft pick on the pile.

Cap issues

But even if the Lions were to find a right deal with the Raiders, that is only half of the puzzle. Mack wants an extension, so not only do the Lions need to find room for is current cap hit of $13.8 million, but they’d have to maneuver the cap to fit Mack on an even higher figure for years to come.

According to the NFLPA salary cap report, the Lions only have just $9.7 million in cap space right now. If Ansah is part of the trade, that’s a very easy way to clear up $17.1 million. But if he’s not, Lions general manager Bob Quinn will have to work some salary cap magic in Mack’s contract extension to minimize his 2018 cap hit.

The good news for Detroit is that their cap situation in the future looks very manageable. They’re currently slated to have $33 million in cap space next year, which is 13th-most according to Spotrac.

We’ve seen teams like the Vikings and Rams crunch some numbers to fit a ton of talent on their roster, but that sort of thing tends to catch up on a franchise. It shouldn’t take Lions fans all that long to remember when former general manager Martin Mayhew kept restructuring deals, leading to a cap-strapped team with little free agent options.

And the deal Mack would be getting would be enormous. Consider the deal that Von Miller got two years ago: six years, $114.1 million. We’re talking over $19 million per year here. That kind of deal would completely change Quinn’s current plan of roster building, and would drastically impact every roster decision he made until Mack’s contract is expired. Golden Tate extension? Probably out of the picture.

So to put a button on all of this:

This is incredibly unlikely to happen as it is literally unprecedented in the NFL. It would cost the Lions an arm and a leg to pry him away from Oakland. Mack’s contract extension is workable in 2018, but would force the Lions to completely abandon their current plans of roster building and force Quinn to work around a massive contract.

So, yeah, it’s probably not happening.