According to ESPN, the Raiders are "strongly considering the acquisition" of Lynch, who has a "Beast Mode" apparel store in Oakland, where he was born and raised. The five-time Pro Bowler will turn 31 in April.
"It could really happen," one source said.
Lynch last played in 2015, when he was limited to seven games thanks to a hernia surgery. Since cryptically announcing his retirement in March 2016, various reports have appeared to leave the door open for a possible return to the NFL.
Back in May, it was reported that Lynch had told multiple teammates he was considering playing in 2016.
"I don't put anything past him," Seahawks cornerback Richard Sherman said of a potential Lynch comeback in May. "He's about as predictable as a pair of dice. So I don't try to call his plays."
To land Lynch, either Oakland would need to acquire him via trade or Seattle would have to release him, because the Seahawks still hold the rights to his contract, which owes him $9 million in 2017 and shomewhere from $7 million to $10 million in 2018, depending on bonuses.
On Thursday, Latavius Murray, who led the Raiders in rushing in 2015 and 2016, signed with the Minnesota Vikings.