The team will hold an introductory press conference Tuesday at noon.
On Friday, ESPN's Adam Schefter reported the Raiders and Gruden came to terms on a 10-year, near-$100 million contract.
The Raiders fired Jack Del Rio as head coach after a disappointing 6-10 mark. Del Rio went 25-23 in three seasons with Oakland.
Gruden hasn't coached since he went 9-7 with the Tampa Bay Buccaneers in 2008, and he has served as a color analyst for ESPN's Monday Night Football since 2009.
He spent his first four seasons as a head coach with the Raiders and went 38-26 with two playoff appearances from 1998 through 2001.
The franchise then traded Gruden to the Bucs, and he won the Super Bowl during his first season in Tampa.
In seven years with the Buccaneers, he went 57-55 and made the playoffs on three occasions.