Healy will be out of contract at the end of the season, but as he has refused to sign a new contract with the Scottish club, they are looking to get rid of him for anything they can.
Celtic boss Martin O'Neill said: “Colin has been offered a new contract and he hasn't signed it and I can understand that. He wants to play first team football and I totally understand that."
Middlesborough and Birmingham City are also interested in the talented midfielder.