The way I see it is.....
Martinez should have around 15M off bill for funds. That comes from TV money and what was left from rodwell and in the current coffers.
After that he should then get 100% from player sales, mainly Heitinga and possibly Naismith, jelavic, whoever he decides to move on.
Seperate to all that is the fellaini situation. If he goes and brings in the expected 25M, I would IF and it's a big IF Rooney is really wanting to come back and willing to make the sacrifice's to enable him to come back, I would move hell and earth to get a deal done with the 25M fellaini money. It would be truly awesome!!
With Rooney in, and around 20M from TV money/player sales to bring in a CB, CM and winger....we'd be really challanging....and very strong.
It sounds so simple, which of course it's not but we can but dream.
Imagine the shirt sales.....Rooney 10