Brown confirmed the deal with a tweet showing him in a Raiders uniform. The deal can become official when the NFL's new league year begins Wednesday.
Sources told the NFL Network that the Raiders also added money to Brown's previous contract with the Steelers. His new three-year deal is worth $50.125 million with a max value of about $54 million. His deal contains $30.125 million in guaranteed money.
Brown originally signed a five-year contract with the Steelers on Feb. 27, 2017, with a $17 million annual price tag. The wideout's deal takes that and turns it into a contract worth $19.8 million each year.
The disgruntled wide receiver and the Steelers had a tumultuous end to last season and it carried over into the offseason. Brown announced his farewell from the Steelers on social media and requested a trade Feb. 12.
Brown has 837 receptions, 11,207 yards and 74 touchdowns in his nine-season NFL career.