The NFL has formally launched an investigation looking into the Oakland Raiders’ head coaching search and whether or not it violated the league’s Rooney Rule, which requires teams to interview at least one minority candidate for a vacant position.

The investigation comes after the Fritz Pollard Alliance, a foundation of former players, front-office personnel, scouts, and lawyers that promotes “diversity and equality of job opportunity” in the NFL, called on the league to investigate whether the Rooney Rule was violated by the Raiders when they hired Jon Gruden as coach.

The Fritz Pollard Alliance is concerned about the process of Gruden’s hiring after owner Mark Davis intimated that a deal with Gruden had all been agreed upon during a meeting on Christmas Eve, when Jack Del Rio was still the coach of the team. Davis eventually fired Jack Del Rio a week later and the team officially hired Gruden on Jan. 6.

Per Pro Football Talk, the NFL has said it does not have a rule or policy preventing a team from reaching an agreement with a new coach before firing the current coach. The fact that there was there was never a “vacancy” at the position could potentially be a loophole to circumvent the Rooney Rule.

Raiders general manager Reggie McKenzie said he interviewed two minority candidates – Oakland tight ends coach Bobby Johnson and USC offensive coordinator Tee Martin – before Gruden's hiring was announced. However, those interviews may have been conducted after an agreement had already been made with Gruden.

As an ESPN report points out, the NFL has issued discipline for Rooney Rule violations in the past. Then-Detroit Lions general manager Matt Millen was fined $200,000 when he was found guilty of breaking the rule in hiring Steve Mariucci as the team's head coach in 2003.