Shemot 21:18-19 discusses the procedure of payment when one person injures another.
Does, say, a professional boxer have to pay his opponent if he injures him during a boxing match? Are the rules different, here, because professionals enter the competition understanding that there is a direct risk of injury?
(My question can be applied to any professional sport using the same scenario. E.g. a tennis player smacks the ball and hits his opponent in the eye.)