Khalil Mack is one of the best defensive ends in the NFL. The problem is he doesn’t have a team to play for, at least not at the moment. The standout defensive star has yet to report to training camp for the Oakland Raiders while he holds out for a new contract, and the longer Mack stays away the more speculation grows that new head coach Jon Gruden and Raiders management may be entertaining the thought of dealing the former 2016 Defensive Player of the Year. The Raiders are on the field this week without Mack in a preseason NFL game [VIDEO].

Detroit a destination?

According to a Lions Daily report, via 247 Sports, it would not be out of the question for Oakland to start searching for a buyer for Mack, and the Detroit Lions are one of the few teams to potentially be on the list.

247 Sports indicated that the Lions have over $33 million in cap space for the 2019 season, however, to really make this deal happen Detroit would likely have to give up either high-round draft picks for the next two seasons, and possibly defensive end Ezekiel Ansah as well.

Ansah, when healthy, has been one of the brightest stars on defense for the Lions since he arrived back in 2013. While Max DeMara of 247 Sports adds that it would be such a steep price to pay for the Lions, adding Mack would be an incredible move for a team that is getting younger and rising in the ranks.

The 27-year-old Mack has been a flat out beast since entering the league. He has accumulated 36.5 sacks over the last three seasons, which is the second most in the NFL during that span. While Mack is due to receive $13.9 million for the 2018 season, he's scheduled to become a free agent in 2019 - and the Lions would have plenty of cap space to afford him.

Patriots, Bears, and Cowboys, Oh My!

While every team in the NFL would love to have Mack on their side rushing towards the opponent's quarterback, it seems that the New England Patriots, Chicago Bears, and Dallas Cowboys top the list of possibilities in obtaining Mack's services. The Patriots and Tom Brady, who is one of the favorites to win the NFL MVP this season [VIDEO], could certainly look tough with Mach on defense.

Just like the Detroit Lions, 247 Sports indicates that these three teams have the cap space in 2019 to not only deal for Mack now but try and strike a long-term deal next offseason as well. Using a franchise tag is always an option, but with a player like Mack, signing him to a three- or five-year deal is what most teams would want to do.

The Bears are in a youth movement like the Lions, however, after parting ways with Pernell McPhee and Willie Young this offseason, Chicago desperately needs help at the outside linebacker spot. Who better than Mack?

How about the Patriots? New England had one of the best offenses in the NFL in 2017, yet boasted one of the bottom third defenses.

Trey Flowers will be a free agent in 2019 and with the possibility of him leaving, Mack would be a great fit for New England. Plus you just know Brady, Belichick and Kraft would love to add another ring to their collection before that era finally fades away.

Others to make the list of strong possibilities to deal for Mack include the Seahawks, Panthers, Packers, Redskins, Falcons and New York Jets.