Dana and Zuffa has something against the camp. They dont like fighter management handling the finances, they basically want to pay fighters as if those fighters are in a Zuffa contract.
Overeem and the rest of the Golden Glory fighters refuse to have this happen, partly because of loyalty, partly because Overeem hired GG to do this job, and mostly because its easier to take advantage of fighters if it operated this way. Afterall how many fighters would have a legal background and know what the fine prints mean.
Sergei will fulfill this last fight for Strikeforce and from what ive gathered, win loss or draw will no longer fight in Strikeforce.
As ive said many times, the way Zuffa operates, the best wont be fighting the best from around the world.