Another solution to this, I'm all three parties might have already considered this, would be to offer him additional money based on the number of goals he scores and the number of games he plays.
Poyet has proven that he will not be held over a barrel for anyone. If Murray's agent feels that he can get him a better deal elsewhere good luck to him. Murray is unproven at a higher level. The money can be used to bring in another player. Players come and players, this is how football is. If...