Jon Gruden said in June that one of the reasons he returned to the sideline was for the opportunity to coach defensive end Khalil Mack.
The Oakland Raiders head coach will need to wait longer for the chance.
Mack will not be among the Raiders' veterans showing up Thursday for training camp, NFL Network Insider Ian Rapoport reported Wednesday. ESPN reported the news first.
Mack, who skipped the team's mandatory minicamp in June, enters the final year deal of his contract on a fifth-year option, which pays a base salary of $13.8 million. Because he is under the fifth-year option, Mack is subject to be fined $30,000 for each day missed in training camp in lieu of $40,000, according to the collective bargaining agreement.
While Rapoport adds the contract discussions between Mack and the Raiders have not gone smoothly -- categorizing the situation as "tense" -- Oakland likely desires to take care of this situation sooner than later when considering what Mack means to the defense.
With double-digit sacks in three consecutive seasons, Mack has made a strong case to earn a lucrative contract.
Since entering the league in 2014 as the fifth overall pick with the Raiders, Mack has established himself as one of the NFL's elite defensive players, totaling 40.5 sacks over the past four seasons. Mack was named a first-team All-Pro selection in 2015 and 2016, and was selected for the Pro Bowl from 2015 to 2017. He was also named the NFL's Defensive Player of the Year in 2016.
NFL Network's Steve Wyche reported in April that Mack seeks a new deal with guarantees in excess of $65 million.