Racket manufacturer Head has congratulated Maria Sharapova after her two-year doping ban was reduced to 15 months.

The five-time Grand Slam champion was suspended by the International Tennis Federation after testing positive for banned substance meldonium in January earlier this year.

Sharapova claimed that the drug - which she had neglected to notice had been added to WADA's list of banned substances - was used for medical reasons.

Today, it was announced by the Court of Arbitration for Sport that Sharapova will now serve a 15-month ban as opposed to two years.

After the ruling, the tennis star's racket sponsor Head tweeted a congratulatory message with the hashtag #WeStoodWithMaria.

The manufacturer's chief executive Johan Eliasch released a lengthy statement congratulating Sharapova on "justice being served", and went on to question the therapeutic use exemptions used by Olympians.

"It is wholly unfair Maria, an upstanding individual of the highest moral and ethical conduct, was banned from playing competitive tennis while not actively engaging in any behaviors [sic] that could be considered cheating," said Eliasch.

"This calls into question the revelations about certain Olympic athletes who were granted therapeutic use exemptions for substances that could most certainly be considered performance enhancing and have been proven to be performance enhancing under significant clinical testing while meldonium, the substance that Maria had been taking, has yet to be proven under any significant clinical testing to have any performance enhancing benefits.

"We therefore conclude that due to the inconsistencies in this case, and many other cases, that there is an urgent need for a wholesale comprehensive review and change to the anti-doping system in identifying performance enhancing drugs and subsequently in informing athletes of the risks associated with the usage of certain substances no matter the circumstances.

"Once again, we are very pleased to welcome Maria back to the sport that we all love, where we have no doubt her true character will shine through and her status as a champion amongst champions will be restored."

Sharapova will be eligible to return to action on April 26, 2017.