The Italian Olympic Committee (CONI) announced today that the Fiorentina striker had tested positive for sibutramine, an anti-obesity drug, after a Serie A game between Fiorentina and Bari on January 10.

"I have spoken to Adrian," said Mutu's agent Victor Becali.

"Clearly he is a little worried but we are optimistic.

"He will probably ask for analysis of the B sample."

Mutu found out about his positive test while training with the team ahead of Sunday's match at Napoli and left the ground early accompanied by the Fiorentina team manager.

The 31-year-old could face a lengthy ban as this is his second failed drug test.

In 2004, the Romania international was sacked by Chelsea after testing positive for cocaine and was given a seven-month worldwide football ban.

After being axed by the Premier League giants and serving his suspension, Mutu joined Juventus in January 2005 before moving to Fiorentina at the end of the following season.

The news has been a hammer blow for the Viola with Mutu having been a pivotal player in Cesare Prandelli's side.

He has struck four league goals in 11 league appearances while scoring three times in six Champions League games.

Fiorentina sporting director Pantaleo Corvino announced earlier today, before CONI issued the Mutu statement, that the club's transfer activity was over for the winter.

He was stunned to hear about the news from reporters, saying: "What are you talking about?"

Fiorentina released a statement later this evening.

It read: "We acknowledge the statement made by CONI regarding the positive tests of Adrian Mutu for sibutramine.

"ACF Fiorentina confirms every opposition to any substance that is banned by the anti-doping rules but believing in the good faith of the athlete, will try to get as soon as possible clarity on the dynamics of this situation."

The Romania international is under contract with the Viola until June 2012.

Mutu will have seven days to decide whether to ask for analysis of his B sample.