This seems unlikely to happen, but stranger things have happened, plus Holmgren has a connection to the Raiders as pointed out by PFT.
Strong and persistent chatter has emerged in recent days linking Holmgren to the job. It’s a fairly obvious connection, given that former Holmgren lieutenant Reggie McKenzie serves as the General Manager in Oakland. McKenzie, who could be the next guy out the door in Oakland, has said he’ll hire the next coach. If McKenzie does, Holmgren could be the optimal Hail Mary option, especially since Holmgren likely would not be inclined to replace McKenzie — unlike other big-name coaches Davis may pursue.
PFT reports Holmgren has been to Raiders facility recently. The Raiders desperately need a big name hire and Holmgren fits the bill.