koubek suspended after drugs test stefan koubek says he has been banned for three months by the international tennis federation (itf) after testing positive for a banned substance.  the world number 60 failed a routine drugs test at this year s french open but now plans to lodge an appeal. koubek believes an injection given to him by an austrian doctor to treat a wrist injury is to blame for producing traces of the substance in his system.  i have acted correctly   the 27-year-old austrian said in a statement. koubek  who defeated britain s greg rusedski in the decisive rubber of the davis cup in september  is now set to miss the start of the season. he said   a three-month ban would mean that i not only will miss the australian open  but also the davis cup in australia.