Khalil Mack’s agent and the Raiders now have a defined rubric off which to build, and it could either bridge them together or — what seems increasingly likely — wall them apart.

Oakland Raiders defensive end Khalil Mack (52) sacks and forces a fumble from New York Giants quarterback Geno Smith during the first half of an NFL football game in Oakland, Calif., Sunday, Dec. 3, 2017. Mack recovered the fumble. (AP Photo/Ben Margot)

Denver Broncos offensive guard Max Garcia (76) blocks Oakland Raiders defensive end Khalil Mack (52) during an NFL football game in Oakland, Calif., Sunday, Nov. 26, 2017. (AP Photo/D. Ross Cameron)

Oakland Raiders defensive end Khalil Mack (52) gestures against the Denver Broncos during an NFL football game in Oakland, Calif., Sunday, Nov. 26, 2017. (AP Photo/D. Ross Cameron)

Oakland Raiders defensive end Khalil Mack (52) sacks and forces a fumble from New York Giants quarterback Geno Smith during the first half of an NFL football game in Oakland, Calif., Sunday, Dec. 3, 2017. Mack recovered the fumble. (AP Photo/Ben Margot)

Oakland Raiders defensive end Khalil Mack (52) sacks and forces a fumble from New York Giants quarterback Geno Smith during the first half of an NFL football game in Oakland, Calif., Sunday, Dec. 3, 2017. Mack recovered the fumble. (AP Photo/Ben Margot)

New York Giants quarterback Geno Smith (3) scrambles from Oakland Raiders defensive end Khalil Mack (52) during the second half of an NFL football game in Oakland, Calif., Sunday, Dec. 3, 2017. (AP Photo/Ben Margot)

Dallas Cowboys quarterback Dak Prescott (4) scrambles away from Oakland Raiders defensive end Khalil Mack (52) during the second half of an NFL football game in Oakland, Calif., Sunday, Dec. 17, 2017. (AP Photo/Ben Margot)

FILE - In this Sunday, Dec. 17, 2017, file photo, referee Gene Steratore (114) carries a folded piece of paper used to determine a measurement next to Oakland Raiders defensive end Khalil Mack (52) during the second half of an NFL football game between the Raiders and the Dallas Cowboys in Oakland, Calif. The NFL on Thursday, Dec. 21, 2017, has told its officials not to use index cards or any other paper to aid in measurements. (AP Photo/Eric Risberg, File)

Oakland Raiders' Khalil Mack looks on during an NFL football game against the Philadelphia Eagles, Monday, Dec. 25, 2017, in Philadelphia. Philadelphia won 19-10. (AP Photo/Chris Szagola)

Oakland Raiders' Khalil Mack in action during an NFL football game against the Philadelphia Eagles, Monday, Dec. 25, 2017, in Philadelphia. Philadelphia won 19-10. (AP Photo/Chris Szagola)

OAKLAND, Calif. — Khalil Mack’s agent and the Raiders now have a defined rubric off which to build, and it could either bridge them together or — what seems increasingly likely — wall them apart.

On Friday morning, Los Angeles Rams defensive tackle Aaron Donald became the highest-paid defender in NFL history. His six-year extension is reportedly worth $135 million with $87 million in guarantees, including a $40 million signing bonus. Mack could receive a similar deal, but it might not be from the Raiders.

Donald’s contract is franchise quarterback money.

The Raiders already have such a deal on their books in quarterback Derek Carr. To offer Mack a deal in Donald’s neighborhood, presuming Mack would accept it, the club effectively would commit to a salary-book structure unlike any other in the league. No NFL team would devote a higher percentage of cash and cap spending on its two highest-paid players than the Raiders.

From the beginning, this has been an underlying reality to these slow-moving discussions. They seemed the price of business to reward Mack, the 2016 AP Defensive Player of the Year. But now, with Donald’s contract done, that reality has numbers. And, according to one report, it very well could lead the Raiders to consider an option they hoped never to entertain.

Trading Mack.

On Thursday evening, a team source acknowledged that several teams have approached the Raiders with trade interest. That same person said the Raiders “want Mack” and have no real interest in dealing him. Relentless work ethic. Well-regarded character. A total of 36½ sacks the past three years. This is someone a team secures, not shops.

This was before the Donald numbers became public. On Friday evening, NFL Network reported that Mack’s trade market indeed is “robust,” and the chance Mack is traded is “very real.”

No deal is known to be imminent. The compensation to acquire the star edge defender, too, would need to be robust.

The Raiders have Mack under contract in 2018. They can retain him once and, should they desire, twice in the coming offseasons with the franchise tag. Coach Jon Gruden is the authority on major roster decisions, though it’s difficult to envision owner Mark Davis standing on the sideline for a situation of this magnitude.

The club might have to receive a Godfather deal, the likes of which the franchise hasn’t seen since early 2002 when then-owner Al Davis traded Gruden to the Tampa Bay Buccaneers. Mack, 27, has yet to practice or attend a meeting since Gruden’s hiring in January.

Entering the fifth-year option of his rookie contract, Mack is due $13.846 million in 2018. This pales to Donald’s new deal, worth $22.5 million per year. Previously, Denver Broncos outside linebacker Von Miller was the highest-paid defender in the league. He signed an extension in 2016 worth $19.1 million annually.

On Sept. 10, Donald will be on the field at the Oakland-Alameda County Coliseum when the Raiders and Rams open their season. The chance that Mack will even be a Raider appears in the balance.

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Contact reporter Michael Gehlken at mgehlken@reviewjournal.com. Follow @GehlkenNFL on Twitter.