B.J. Penn thinks Khabib left early

"I loved watching Khabib Nurmagomedov fight. I haven't seen him ever call himself the greatest lightweight of all time, that's not his style. But I will say my opinion on his career. He left way too early. There are fighters and there are athletes, and all I ever wanted to do was fight, anyone. I don't know who the greatest lightweight in history is... I was only here to fight," the fighter wrote on his Instagram.