( CNN ) -- Tennis is 'likely ' to change one of its anti-doping rules after Viktor Troicki received an 18-month suspension for refusing to take a drug test at a tournament earlier this year . Troicki was hit with the ban after he opted against giving a blood sample at the Monte Carlo Masters in April , citing poor health . He provided a urine sample . The Serb claims the doping control officer on site allowed him to take the blood test the day after but the International Tennis Federation ( ITF ) says that was n't the case . When he did take the blood test the following day , Troicki said , it came back negative . Troicki , who is taking his case to the Court of Arbitration for Sport next week , said in a statement released Tuesday that good friend and world No . 1 Novak Djokovic was the first player to sign a petition demanding new rules at the `` doping control station if there are problems . '' The ITF said Wednesday there would indeed probably be alterations next year to avoid any possible confusion . `` The tennis anti-doping rules are likely to be changed in 2014 to say that , where a player refuses or fails to provide a sample ( as Mr. Troicki did ) , the doping control officer should try to offer the player an opportunity to speak to the event supervisor or referee to confirm the player 's responsibilities under the program , '' Stuart Miller , the ITF 's anti-doping manager , told CNN . When asked if the change of thinking was due to the Troicki affair , Miller added : `` I think it 's fair to say that the Troicki case highlighted the issue . `` Given this only happened in 2013 , I think it 's looking at the problem pretty quickly and trying to find a solution . '' Troicki , a former world No . 12 , said other players were `` worried '' in the wake of his suspension . `` The players demand that the tournament supervisor or the ATP tour manager must be called to the doping control station if there are problems , '' the 27-year-old said . `` No one should leave the room without providing samples if one of them has not been called . `` The players are worried . What happened to me could have happened to them . '' CNN was unable to verify if Djokovic signed any petition , although he told reporters at Montreal 's Rogers Cup in August : `` We all give ( Troicki ) big support because he 's definitely innocent . '' Troicki said he was `` confident '' ahead of his hearing in Lausanne , Switzerland on October 9 . `` I am fighting for the truth and I will do it as hard as I can , '' he said . `` I have done nothing wrong , apart from following the instructions of the doping control officer . `` I really put all my hopes in the judges that will decide in Lausanne . I hope they take their time and that they really find the truth . I do n't even want to think about anything else . ''
Tennis will probably change one of its anti-doping rules in 2014 following Viktor Troicki 's ban . The ATP said it would allow players to use the banned substance meldonium if they had a doctor's note from their doctor saying that Meldonium, which is used as an appetite suppressant and for Troicki claims he was told he could take the test the day after but the ITF refutes that . Troicki says Novak Djokovic was among those who signed a petition demanding rule changes .