No such thing as ‘just a little sharia”.
Yes, there are those who argue the right and legality of Muslims arbitration courts, that ‘similar arbitration venues’ are set up to decide issues (outside of the U.S. court system) for a host of different other groups and societies. However, I know of no football team, or any other sports league, let alone or other religious groups whose own ‘legal system’ affects others outside their groups, unlike Islam.
H/T: Vlad