Sheffield United are ready to sell Paddy Kenny for £5 million to either Newcastle United or Middlesbrough.
The Republic of Ireland keeper is angry at being dropped by Blackwell after he turned up late for training on Christmas Day. They also fell out earlier this month over a new contract.
A source told the Mirror: "Paddy's fed up with the way talks have dragged on. He thinks the club are taking the mickey and he feels unwanted."