Since he arrived in the NFL, Oakland Raiders defensive end Khalil Mack has been one of the league's most dominant pass rushers. He's nearly unblockable one-on-one, recording 40.5 sacks while reaching three Pro Bowls and a pair of First-Team All-Pro honors in his first four seasons. He's the cornerstone of the Raiders' defense and arguably the team overall, outside of starting quarterback Derek Carr.

So, when rumors came out this week about the Raiders possibly considering moving Mack as he continues to hold out from training camp, the idea seemed crazy. Yet, according to an NFC executive who spoke to Bleacher Report's Mike Freeman, the chances of Mack being moved grow by the day.

The odds of such a trade were zero percent a few months back, but now they are 20 to 30 percent and increasing every day, one NFC team executive said.

“There's a feeling the Raiders are open for business when it comes to Mack,” the exec said.

Currently, Mack is set to make $13.846 million on the fifth-year option of his rookie deal. So far, both sides haven't come close to an agreement, with Mack reportedly looking to garner a contract similar to Denver Broncos outside linebacker Von Miller's 6 year, $114.1 million deal with $70 million guaranteed.

Despite Mack's prowess, Oakland's defense has struggled as an overall unit the past few years. With more help from his fellow defensive linemen and Oakland's secondary, Mack's numbers would arguably be even better.

Oakland won't simply give away their superstar defender without a huge haul in return. The Green Bay Packers have been mentioned as a possible landing spot with two 2019 first-round picks at their disposal, and ESPN's Paul Gutierrez also noted that the Tampa Bay Buccaneers possess the assets necessary to potentially entice the Raiders.

Still, at the end of the day, many pundits aren't buying that a Mack trade will occur in the end.