My biggest concerns at this point are the length of time Maria Sharapova was on this substance and how she obtained/used this substance given that her training location is in the US and the FDA does not approve of this substance.  These two questions are the most problematic to my mind thus far, but I hope more clarity comes soon.  The biggest threat to tennis on a whole would be a revelation that many players take some sort of supplement that violates the spirit of the rules if not the letter of the rules.