From the Spanish paper, Marca, they note that Real Madrid is attempting to extend Mirotic's contract which already extends out to 2016 (though it has a 2.5 million dollar buy out this coming season).
Can Real Madrid realistically pay Mirotic?
Perhaps, perhaps not. It's up for debate how much the Bulls would realistically go on Mirotic, and it's definitely a possibility that they could up their offer enough to keep Mirotic's interest from heading to the NBA a couple years further away.
Since he already has a 2.5 million dollar buy out this season, of which the Bulls can only pay 600k, Mirotic will expect to make only around three million (with nearly two million of his MLE deal going to Real Madrid for this buyout) this coming season. Factor in taxes, and next year he probably makes more in Real Madrid.
However, after that, it might be tough for Real Madrid to contend with what the Bulls can offer if they go a full five million and full MLE. The question becomes for both sides, how many years do you put on the contract?
The Bulls would likely want three years [full bird rights and Mirotic is a restricted FA] while Mirotic could want anything from two to four years [two to get out of his deal quicker and try and reup for more than the MLE or four to ensure that he locks in considerably more money after losing some money from his buyout.
The fourth year is a killer for the Bulls, as if they do a fourth year they won't have RFA rights on him when he's a free agent. Rookie scale deals end with restricted free agency, but because Mirotic is no longer bound by the rookie scale, his deal would only end with the Bulls have restricted free agency rights on a three year or less deal.
It will be an interesting negotiation either way.
The short story is this. If Real Madrid makes a real offer and Mirotic accepts then he's likely over there for quite some time. Any new offer will almost certainly keep an NBA prohibitive buyout amount on the books for him. It also sounds like any renegotiation that takes place will be aimed at keeping him long term not just leaving him there for another season.
If Chicago is looking to make Mirotic a part of their core, they need to get him over as soon as possible. His development will be limited in Europe at this point. Up until now, it's likely been much better training than college, but he needs to start playing against NBA caliber athletes on a regular basis to improve his NBA potential sooner rather than later.
After a season already ruined by Rose's injury, the Bulls need to find a way to get Mirotic here next season in order to instill some hope and fresh blood into the line up.