The biggest name remaining in free agency has been taken off the market thanks to a last-minute push by a fitting team.
"I'm a Raider," said Sapp when contacted on his cell phone. Sapp, however, would not elaborate on the terms of the deal or comment when the deal would be announced.
Sapp will receive a $7 million signing bonus. He earned $6.6 million last year in the final season of a six-year, $36 million contract he signed in 1998.
The Bengals had offered $16 million over four years with a signing bonus that exceeded $4 million. Sapp also had marginal interest from a few other teams.
Ravens star linebacker Ray Lewis and defensive coordinator Mike Nolan made a strong push to their front office to sign Sapp, but the perennial Pro Bowler said he wanted to have a new home by Monday morning.
Sapp awoke on Saturday morning to an offer from a team he has long stated he belonged with -- the Silver and Black. He joins Ted Washington, another veteran Pro Bowl defensive tackle, in the Raiders new defensive line under new head coach Norv Turner.
Earlier this month, the 31-year-old tackle said he was optimistic about the prospect of re-signing with the Bucs. But that changed when his old team failed to make him an offer during the first week of the free agency period.
Sapp joined the Bucs as first-round draft pick out of Miami in 1995 and -- along with linebacker Derrick Brooks and safety John Lynch -- helped transform the Bucs from a laughingstock into Super Bowl champions.
Lynch was released last week after 11 seasons with Tampa Bay, a move that cleared about $4 million under the NFL salary cap.
Sapp leaves the only pro team he has played for two sacks shy of the franchise record of 78½ held by Hall of Famer Lee Roy Selmon.
The Associated Press contributed to this report