Tennis community stunned by Sharapova's failed drug test

What is meldonium? (0:47)

ESPN's Pam Shriver explains why the International Tennis Federation added meldonium, the drug Maria Sharapova was caught with in her system during the Australian Open, to the banned substance list in January 2016. (0:47)

During a press conference Monday in Los Angeles, Maria Sharapova, a five-time Grand Slam champion, announced she had failed a drug test at the Australian Open.

Needless to say, fellow players and analysts were quick to react to the stunning news.