Moscow: Tennis star Maria Sharapova would need at least six months to get back into shape to display decent results at international tournaments following her comeback next month in April, Russian Tennis Federation (RTF) president Shamil Tarpishchev said.

Currently sitting out a provisional suspension due to doping violations, the 29-year-old is set to make her comeback following a doping ban on April 26 at Stuttgart, reports Tass news agency.

"Sharapova is currently in her full-swing preparations for the comeback," Tarpishchev said in an interview with Tass on Monday. "However, one should not immediately expect victories and new trophies from her."

The former world No.1 has already picked up wildcards for tennis tournaments in Stuttgart, Madrid and Rome, as she is making her return to the WTA circle following her suspension due to the presence of the banned performance enhancing drug, meldonium, in her body.

"It will take her at least half a year to adjust to the fiercely competitive schedule after the comeback," the Russian tennis chief added.

The tennis player has been serving a two-year suspension for the violation of anti-doping regulations since January 26 last year.

However, the Swiss-based Court of Arbitration for Sport (CAS) ruled on October 4, 2016 to reduce her suspension term from 24 to 15 months.

Last March, Sharapova announced that her doping tests revealed the .

Sharapova is Russia's most decorated tennis player having won a total of five Grand Slam tournaments, namely the Australian Open in 2008, the French Open in 2012 and 2014, Wimbledon in 2004 and the US Open in 2006.

She also clinched a silver medal winner of the 2012 Summer Olympics in London and the 2008 Federations Cup champion.