The Fitz Pollard Alliance, an advocacy group that promotes diversity in NFL front offices and coaching staffs, asked the NFL to investigate whether the Raiders reached an agreement with Gruden before interviewing minority candidates.
"As soon as we learned of the reports, we formally requested that the NFL thoroughly investigate the matter to conclusively determine whether the Rooney Rule was violated -- and if it was violated, to impose an appropriate punishment," Fitz Pollard Alliance counsel Cyrus Mehri and N. Jeremi Duru said in a statement obtained by NFL Network's Steve Wyche.
Raiders general manager Reggie McKenzie said that he interviewed two minority candidates prior to Gruden's hiring on Saturday. Those candidates were Oakland tight ends coach Bobby Johnson and USC offensive coordinator Tee Martin.
The Rooney Rule requires teams to interview at least one minority candidate as part of an open process.
Prior to Gruden's official hiring, the Fritz Pollard Alliance initially downplayed concerns that the Raiders were in compliance with the Rooney Rule.
That stance changed during Gruden's introductory news conference on Tuesday, when Raiders owner Mark Davis said he met with him on Christmas Eve, and felt "pretty confident that he was all-in" after their meeting. The Raiders fired Jack Del Rio a week later and the team officially hired Gruden on Saturday.
"...That's the term that we were using in our discussions and everything, are you all-in? And I never wavered from all-in. And this time he didn't waver, either," Davis said.
Davis also said on Tuesday that he had been pursuing Gruden since taking ownership of the team from his late father, Al, six years ago.
"For someone to say for six years, 'When you are done broadcasting, we would love for you to compete here for a job as the head coach of the Raiders,' that is not a violation of the Rooney Rule," Mehri told ESPN on Wednesday night. "If in December, Gruden says to Davis, 'Hey, I am going to come out of the broadcast booth and I'm ready to coach again,' that is not a violation of the Rooney Rule.
"But if in December, Gruden and Davis reach an agreement -- not necessarily a written, contractual agreement, but a verbal agreement -- that Gruden was going to coach for the Raiders, and then after that they do these interviews with minority coaches, that would be a violation of the Rooney Rule."
The NFL has issued discipline for Rooney Rule violations in the past. Then-Detroit Lions general manager Matt Millen was fined $200,000 for circumventing the rule when he hired Steve Mariucci as the team's head coach in 2003.
Gruden left the broadcast booth at ESPN to return to the franchise where he spent his first four seasons as a head coach. He posted a 38-26 regular-season record (40-28 overall) from 1998-2001 and guided the team to a pair of playoff berths, including appearances in the AFC Championship Game in his last two seasons.
Known for his feisty sideline demeanor, Gruden admitted he has some "unfinished" business with the Raiders. His final game with Oakland was among the most controversial losses in NFL history, when the Raiders lost to the New England Patriots on the infamous Tom Brady "Tuck Rule" non-fumble call.
Gruden was traded to Tampa Bay in 2003 and proceeded to guide the Buccaneers to a Super Bowl championship in his first season. Overall, he is 95-81 in 11 regular seasons and 100-85 including the postseason.
Gruden succeeded Del Rio, who was fired following a season-ending loss to the Los Angeles Chargers that capped a disappointing 6-10 campaign for the Raiders.