Raiders senior executive John Herrera confirmed the trade, but he said it won't become official until the league approves it and Curry passes his physical.
Fox Sports reporter and NFL Network contributor Jay Glazer first reported the deal.
A league source told NFL Network insider Jason La Canfora that the Seahawks had been shopping Curry, the No. 4 overall pick in the 2009 draft, since he lost his starting spot to rookie K.J. Wright after a Week 2 loss to the Pittsburgh Steelers. Curry first expressed frustration at the benching, then said a few days later that he was at peace with the decision.
Curry was absent from Seahawks practice Wednesday, and his locker was cleaned out. Some of his former teammates confirmed Curry had come to the Seahawks' facility earlier in the day to say his goodbyes.
"He came in and said how much he had learned from us and how much he's going to miss us and everything," linebacker Leroy Hill said. "It's a new beginning for him, and hopefully he steps to the plate. I think down there, he won't have all those high expectations that he had here, so he can relax and just play ball. I wish him luck and think everything will work out for him."
Curry, a Butkus Award winner taken No. 4 overall in the 2009 draft, hasn't been able to make the complete transition to the pro game. He struggled, especially in pass coverage, to the point where he was replaced by recent free-agent signee David Vobora at times in the fourth quarter of last week's 35-26 victory over the New York Giants. Vobora had just been re-signed by the Seahawks earlier that week.
Curry allowed eight receptions on eight attempts in his direction for 120 yards, according to STATS LLC. For his career, Curry has allowed 62 catches in 76 attempts for 613 yards and six touchdowns for a 126.6 passer rating.
The Raiders, who made their first move since the Saturday death of longtime owner Al Davis, need Curry because they are banged up at linebacker, with starting middle linebacker Rolando McClain slowed by an ankle injury and backup Ricky Brown placed on season-ending injured reserve last week. Starting strongside linebacker Kamerion Wimbley also could see more time as a rush defensive end with starting end Matt Shaughnessy out with a shoulder injury.
Acquiring Curry is the type of deal that Davis, who also served as general manager and ran the Raiders' football operations, probably would have liked. Oakland often has been successful acquiring former high draft picks who were struggling elsewhere. Curry would be the 12th former first-round pick on the Raiders' roster, including seven on defense.
Curry's future in Seattle already was tenuous after his contract was restructured this year, with the linebacker giving up a large chunk of guaranteed money that was expected to come his way in 2012 and freeing the Seahawks to part ways with him after this season.
The Associated Press contributed to this report.