Steve Corkran of the Raiders Snake Pit was first with the news of Gruden's return.
Yes, that infamous Tuck Game, in which the Patriots defeated the Raiders 16-13.
Gruden famously won Super Bowl XXXVII with the Tampa Bay Bucs back in 2003. when he beat the Raiders.
Gruden's contract will be worth around $100 million over 10 years, according to Schefter.
The Raiders fired Jack Del Rio as their coach last Sunday, just after completing a 6-10 season.
He amassed a 57-55 record in seven seasons as Tampa Bay's coach.
Gruden posted a 38-26 record with Oakland from 1998-2001, guiding the team to a pair of playoff berths and the AFC Championship game in his last two seasons. Gruden has already started putting together a staff with Cincinnati defensive co-ordinator Paul Guenther among those expected to join.
Many speculated that the Raiders broke the Rooney Rule, which is a league policy that requires NFL teams to interview minority candidates for coaching and senior football operation positions.
"I can tell you we believe the Rooney Rule was complied with", Lockhart said. ESPN reported that Davis was in hot pursuit for Gruden with a persuasive offer that included an ownership stake in the Raiders. Gibbs stepped away following the 1992 season with three Super Bowl titles in his career.