VIENNA (AP) Maria Sharapova's racket supplier says the drug she tested positive for at the Australian Open shouldn't be on the banned list.

''We question WADA's decision to add meldonium to its banned substances list in the manner it did,'' Head CEO Johan Eliasch said Friday, one day after he publicly backed Sharapova and announced a new racket deal with the five-time Grand Slam champion, who has been using the equipment since 2011.

Eliasch said the World Anti-Doping Agency should have imposed ''a dosage limitation only'' on meldonium instead of completely banning it as of Jan. 1.

According to Eliasch, Sharapova was taking the substance in such low doses that the drug couldn't possibly have improved her performance.

''In the circumstances we would encourage WADA to release scientific studies which validates their claim that meldonium should be a banned substance,'' he said.

Eliasch's comments appeared on Head's website Friday. The Austrian-based company publicized a shortened version of the CEO's statement on the extended sponsoring of Sharapova from the day before but added a paragraph which wasn't included in his initial comments.

The decision to renew the deal with Sharapova was called ''a strange stance'' by Andy Murray, who also plays with Head rackets. The British player was asked about the matter at the BNP Paribas Open in Indian Wells on Thursday.

Murray said he would have responded in a different way, and that Head should have waited with its decision on a contract extension ''to get hold of the facts'' until ''more information coming out.''

Still widely used in Eastern Europe, meldonium is a blood-flow drug that historically was used to improve Soviet soldiers' endurance.

Sharapova said this week she had been taking the drug for 10 years for various health issues, and that she failed to check the new list of banned substances before the start of 2016. She faces a lengthy ban and could miss out on competing for Russia at the Olympics in Rio de Janeiro.

Several other brands, including sports gear giant Nike, watch maker TAG Heuer, and sports car company Porsche, suspended their support of the world's highest-earning female athlete after her announcement that she failed the drug test.