Maria Sharapova's wildcard entry into the Stuttgart Open has been defended by WTA chief Steve Simon who said it is in keeping with how former dopers are treated in other sports.
The 30-year-old Russian's 15-month ban for using meldonium ends on Wednesday when she plays in the first round.
"You have to look at how other leagues and tours have handled players who have come back," Simon told BBC Sport.
"They come right back to the team and start playing."
Italy's Roberta Vinci - Sharapova's opponent in her comeback match on Wednesday evening - disagrees with the decision to invite the five-time Grand Slam champion into the main draw.