( 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 . Troicki received an 18-month suspension after failing to provide a blood sample in April . 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 .