Maria Sharapova says she is retiring from professional tennis at the age of 32. The five-time Grand Slam title champion and former No. 1-ranked player has been dealing with shoulder problems for years. She played only two matches this season and lost both. Sharapova burst onto the tennis scene at 17 when she won Wimbledon in 2004. She would go on to complete a career Grand Slam with two titles at the French Open and one each at the U.S. Open and Australian Open. She served a 15-month ban after failing a doping test in 2016.