Croatia's Marin Cilic returns the ball during his men's singles tennis match against Tomas Berdych of the Czech Republic at the Queen's Club Championships in west London, June 14, 2013. [Photo/Agencies]

ZAGREB - Croatian tennis player Marin Cilic said on Monday he would make an appeal after International Tennis Federation (ITF) decided to suspend him for nine months for a banned supplement.

"I will be appealing that decision to the Court of Arbitration for Sport very shortly", the 24-year-old player said in a statement.

He said that the substance in question originated from a glucose tablet purchased at a pharmacy in France. He did not known tablets contained a substance that is banned in-competition.

ITF announced on Monday to impose on Cilic a nine-month ban for the stimulant nikethamide, saying he "ingested the nikethamide inadvertently as a result of taking Coramine glucose tablets, and did not intend to enhance his performance in doing so."

The suspension has been backdated to May 1, which means the Croatian highest ranked player, who is currently ranked 24th, spent 11 successive weeks in the top 10, will miss the Australian Open.

Cilic's doping violation came when he tested positive for nikethamide at the BMW Open in Munich in May when he reached the last 16 but that result is now null and void, while ranking points and prize money won since that tournament and up until his suspension will be forfeited.

Cilic has not played since withdrawing from his second-round match at Wimbledon in June.