http://revach.net/article.php?id=3890

Section: Halacha   Category: Health
Rav Moshe Feinstein: On The Dangers Of Becoming A Professional Athlete
Rav Moshe Feinstein (Igros Moshe CM 103) was asked if someone may embark on a career as a professional athlete despite the danger involved (this tshuva focused only on the danger and not any other halachic or hashkafa issue). 

Rav Moshe said it was permissible to earn a livelihood that involves danger despite the fact one in a few thousand can be seriously injured or even killed.  This applies to any hazardous profession where the odds are very low, yet still a danger is present.  Moreover says Rav Moshe, it is permissible to do work that may end with you causing the death of another person.

He brings proof from the gemara (Bava Metzia 112) that discusses the wages of an employee, and brings a pasuk that a worker risks his life by climbing high trees to cut the produce.  Rav Moshe's reasons that there is no difference between the issur of killing yourself and killing others.  Either way if the chances are very slim, then to earn a living it is permissible.  If this wouldn't be so, says Rav Moshe, then how was the owner able to employee this daredevil worker?  However, says Rav Moshe, it is only permissible to employ someone for a dangerous task if the person is aware of the dangers involved and consciously accepts the risks.

Important Note: We try to convey the Tshuva to the best of our ability. We admit that our understanding may not be accurate. One should learn the tshuva to verify the accuracy of our interpretation.  Please also understand that this Tshuva may not be the final word on this topic. One should consult a Rav before drawing any conclusions.