NFL teams are not crazy about HBO's Hard Knocks, and why should they be? Why would teams want their personal business during training camp out there for the world—which includes other NFL teams—to see?

As a result, the NFL sometimes has to force Hard Knocks on teams that do not want to do it.

It's annoying, but by league rules, a team can be forced into appearing on HBO if they haven't done it in the last 10 years, have not been to the playoffs over the last two years, or don't have a new head coach.

Thus far, the Cleveland Browns, Tampa Bay Buccaneers, Los Angeles Rams, Houston Texans, Atlanta Falcons, Cincinnati Bengals, Miami Dolphins and New York Jets have all participated in Hard Knocks, so they are in the clear.

You then have a host of teams you have been to the postseason across the past two seasons, and you will have a bunch of teams that will be entering the 2019 campaign with a new head coach.

However, per Michael David Smith of Pro Football Talk, there are five ballclubs who currently do not check any of those boxes: the Detroit Lions, Oakland Raiders, New York Giants, San Francisco 49ers, and Washington Redskins.

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All five of those teams can be forced into doing Hard Knocks, unless, of course, one of their head coaches gets fired between now and training camp.

Who knows? Maybe one of the franchises will fire a head coach on purpose just so they don't have to appear on the show?

But in all seriousness, the Raiders seem to be the most attractive candidate here, given Jon Gruden's presence and the fact they just hired TV personality Mike Mayock as their general manager.