It is understood that Keegan's three-and-a-half-year contract contains a clause stipulating whichever party terminates the deal owes the other £2million.
Keegan, however, may argue that he has a case for constructive dismissal after finding himself unable to work alongside Wise.
Godwin Busuttil, a barrister at 5RB in London, explained: "I would guess the fault line of this argument is going to be Keegan saying, 'You Ashley/club have breached this contract first, you repudiated it by putting me in a position whereby I couldn't carry out my managerial, contractual functions.
"'You breached the contract. You put me in a position, you forced me to go. That is called constructive dismissal. Effectively, it means, I had no choice but to go'.
"The club would say, 'No, you resigned. You didn't have any good reason to do that. You breached the contract'.
"Unless they can sort out that difference between them, then a court will have to sort it out. A judge will have to decide the rights or wrongs, or perhaps an arbitrator."
LMA chief executive Richard Bevan told Sky Sports News: "I think I'd like to see Newcastle - rather than coming out and saying they are going to sue Kevin Keegan for £2million - talking about how they are going to improve for the next manager."