Russian Tennis Federation president Shamil Tarpishchev is confident Maria Sharapova will return to competitive action in January.

Five-time grand slam champion Sharapova was banned for two years by the International Tennis Federation in March after testing positive for banned substance meldonium at this year's Australian Open.

The former world number one claimed to be unaware that meldonium had been added to WADA's prohibited list at the start of 2016.

Sharapova appealed the ruling with the Court of Arbitration for Sport, with a decision on that due in September after a delay to enable further evidence to be gathered.

And Tarpishchev believes the 29-year-old will win her appeal, and be back on the WTA Tour as early as next year.

"A decision will be made in September," he told Russian news agency TASS.

"I'm not certain but I believe that she'll start playing as of January 2017."

Sharapova has not played on tour since her quarter-final defeat to Serena Williams in 2016's first grand slam.