Andy Murray, Maria Sharapova

Tennis can be a lonesome sport. With no teammates, the most common peer support players get is from each other in locker rooms around the world. Exhibit A: Serena Williams expressed immediate support for Maria Sharapova after the five-time grand slam champ failed a recent drug test.

Andy Murray, the men's World No. 2, is not lending the same comfort. The consistently brash Brit spoke about Sharapova Thursday at the BNP Paribas Open in Indiana Wells, California.

Maria Sharapova

"It's not up to me to decide the punishment, but if you're taking performance enhancing drugs and you fail a drugs test, you have to get suspended," Murray says. "If you're taking a prescription drug and you're not using it for what that drug was meant for, then you don't need it, so you're just using it for the performance enhancing benefits that drug is giving you. And I don't think that that's right."

Sharapova's positive drug test was for meldonium, a drug produced in Latvia and sold over the counter in parts of Europe, including Russia. Sharapova, who was born in Russia and represents Russia, trains in the United States, where meldonium is not available for purchase. The World Anti-Doping Agency added the drug to its list of banned substances in January, just before Sharapova's failed test at the Australian Open.

Meldonium is typically given to people suffering from heart problems, but as Reuters says, "It can also increase blood flow and improve exercise capacity." Sharapova, who says she has been taking the drug for 10 years, claims a family doctor advised the drug because she was constantly getting sick, had irregular electrocardiogram results, a magnesium deficiency and a family history of diabetes.

Murray doesn't buy it.

"I read that 55 athletes have failed tests for that substance since January 1," Murray says. "You just don't expect high-level athletes at the top of many different sports to have heart conditions."

Andy Murray

Also at Indian Wells, former World No. 1 Rafael Nadal said Sharapova must pay for her "negligence."

Sharapova will be provisionally suspended this weekend and faces up to a four-year ban by the International Tennis Federation. The highest-paid female athlete, Sharapova has already lost sponsorship deals from TAG Heuer, permanently, and Nike and Porsche on an indefinite basis.

Head, Sharapova and Murray's racquet sponsor, actually extended her contract by five years this week.

Murray called this behavior from the company "strange" and adds, "I don't really know what else to say on that, but that's not something I believe. I think at this stage it's important really to get hold of the facts and let things play out, like more information coming out before making a decision to extend the contract like that, in my view. I personally wouldn't have responded like that."

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-- Follow Jeffrey Eisenband on Twitter @JeffEisenband.