Eighteen-time Grand Slam champion Chris Evert has admitted that she has found the lack of support for Maria Sharapova "surprising" in the wake of the Russian's failed drug test.

Sharapova admitted earlier this week that she had tested positive for a banned substance at the Australian Open having failed to notice that meldonium had been added to the list of prohibited drugs.

Serena Williams spoke out in support of the 28-year-old, but she is one of few to have offered her backing, which Evert has been surprised to see.

"Maria Sharapova has always isolated herself from the rest of the tennis world. She's made that known, she can't be friends with the players. I'm not seeing a lot of support from a lot of the players. I think everyone is being mum right now," Evert told ESPN.

"Whether it's shock or whether they don't want to become involved or have an opinion about it, it's sort of surprising that not a lot of players have shown their support for her. It's just incredulous to me because she has such a very comprehensive and a very professional team. For everybody in the tennis world, Maria Sharapova is the last person we'd expect this to happen to.

"To me, it's a good warning to all the superstars out there that they mean serious business and that the sport is not protecting you if you're bringing in money for the sport, if you're bringing in TV ratings - it doesn't matter who you are."

Sharapova, who is a five-time Grand Slam champion, will be "provisionally suspended" from March 12.