The announcement was made about an hour after Gruden had finished working as an analyst at the National Football League wild-card game between Tennessee and Kansas City on Saturday.
"Well thank you", demurred Gruden, who is set to be introduced as the Raiders' head coach on Monday.
Gruden's 10-year, $100 million contract is the richest in National Football League coaching history and matches Tom Landry and Jimmy Johnson (both with the Cowboys) for the longest, the Times reported.
"I'm Sean McDonough along with the coach, Jon Gruden".More news: Sessions nixes Obama-era rules leaving states alone that legalize pot
The Buccaneers went 12-4 in his first season and finished 57-55 with three playoff appearances in Gruden's seven seasons.
This would not mark the first time the Raiders brought back a coach for a second stint. He served in that role from 1998 through 2001, before being traded to Tampa Bay.
The team finishing in third place in the AFC West, again failing to qualify for the playoffs. Raiders have rehired coaches before but the results were not what they were hoping.
The Chiefs weren't the only ones who had their run this season ended at Arrowhead on Saturday. It won't happen Saturday, because Gruden has obligations with his current employer, ESPN, and it won't be Monday because that's when he's expected to "interview" for his new gig. While the quality of the Monday Night games for ESPN hasn't been that great, folks have tuned in to hear what a souring relationship sounded like in real time. He last coached the Tampa Bay Buccaneers in 2008. In 2011 he was on camera for the Outback and Orange Bowl games.