As @mattm states, the risk of transmission is low. This does not mean that it doesn't exist, but the likelihood of it happening is actually very low.

Just from a knowledge standpoint, you are much more likely to contract a bloodborne pathogen (BBP) other than HIV. HIV is actually somewhat low on the virulence scale, in that you need more exposure than other pathogens to contract it. It also requires direct blood contact to open wounds or mucousal tissue.

This has been studied quite a bit, and the general stance is that this is a low transmission risk. Here are a couple of references to start research (The second is a stub, but has links to the cited studies which you can usually find on google scholar): 

[Human Immunodeficiency Virus and Other Blood–borne Viral Pathogens in the Athletic Setting][1]

[Blood borne pathogens in sports][2]

[Google Scholar studies/articles][3]


  [1]: http://pediatrics.aappublications.org/content/104/6/1400
  [2]: https://www.uptodate.com/contents/bloodborne-pathogens-and-sports
  [3]: https://scholar.google.com/scholar?hl=en&as_sdt=0%2C3&q=blood%20borne%20pathogens%20and%20sports&btnG=