He joined the Tigers in 2000 from Port Vale, making 95 appearances for the club.
He had been linked with a return to Scunthorpe then, even playing for the club in a pre-season friendly at Goole.
Now he is tipped to join the Iron as competition for Tommy Evans, with Boston also chasing his signature.
Hull manager Peter Taylor told the Hull Daly Mail: "Paul knows the situation and I really hope Scunthorpe or Boston - who I've been told are interested in him - do sign him up.
"He's a cracking lad and I want him to be happy and find regular first-team football somewhere."