A move to the Championship is edging closer for the midfielder with Derby County and Charlton Atheltic his closes pursuers at present.
The Cobblers are keen to negotiate a fee for the player without having to go to a tribunal and then hand a percentage of the money to Aidy Boothroyd to build a promotion-winning squad.
"I suspect that Michael will not sign his contract and will want to move on,” said Sixfields chairman David Cardoza, quoted in the Chronicle & Echo.
“I can understand that because there are some big clubs out there who have already had a couple of offers turned down.
“We are expecting more interest as the summer progresses and we want to get it done as soon as possible."