It depends if Khabib decides to fight Tony next.
For a guy who has been recently called out by Mayweather, Conor McGregor, GSP and Tony Ferg. It's kind of hard to pick someone like Tony Ferg to fight because he's high risk, low reward in that he will bring the least PPV buys of all those guys I just mentioned.
HOWEVER if Khabib is sincere about fighting for other things than just money, it would make sense for his legacy to have that fight with Tony next but we all know that no man is safe from greed. Even a religious mountain type, greed and money and sin can get to any man.