In the past Khabib has said he wants Tony next then GSP.
If the UFC wants to let GSP come in and get the third weight class title fight and then walk away (which Dana says they don't) then I think the best way for UFC to do it is this... let Khabib vs Tony finally happen.
Even if Tony wins... GSP can come in and try to win the third title from the guy who is 13-0 and just beat Khabib.
This way the UFC gets Khabib vs Tony and winner vs GSP.
If the UFC does Khabib vs GSP right now... if GSP wins then the Tony fight is ruined and GSP walks away.
UFC only gets big fight out of the deal if they do GSP vs Khabib right now, they get two giant fights if they hold GSP back for the winner.