Shaykh Asrar Rashid:

“So, there are two things to this. Firstly, take Khabib, for instance, the MMA fighter. He beat up a kafir. I forget the name—McGregor. Now, that man was a kafir in the sense that he insulted Islam, so Khabib was permitted to beat him up. This would count as Jihad. Muhammad Ali also beat up men who did not respect Islam, and he was permitted to do so. In those cases, what the fighters did would count as jihad, and it was permitted.

Now, if you are not as skilled as Khabib or Muhammad Ali, and you do not fight for the prestige of Islam or for the sake of Allah’s word, then the fatwa would apply to you. For instance, if you have sponsors that are haram, wear shorts that are impermissible, or strike the head and face, or if taking a beating then it does not count as jihad, then it would be haram. So, anyone participating in MMA or boxing—if you are doing this for the prestige of Islam, then enter the field and become like Khabib or Muhammad Ali, and that would be permitted.”

@ShAsrarRashid