Croatia\'s double world high jump champion Blanka Vlasic revealed Tuesday she may not be fit to compete in the 2012 Olympics after undergoing left foot surgery. \"Both this season and the Olympic Games are questionable. Unfortunately, I have to be realistic,\" Vlasic told journalists. \"I will not give up London, but I will not take any risk either. \"I know my body very well and when the time to leave for the Games comes I will know whether I\'m ready,\" the 28-year-old added at a press conference in her hometown of Split, on the central Adriatic coast. Vlasic underwent arthroscopic surgery on the Achilles tendon of her left, take off foot, in January in Sweden and gradually started to train. However, due to constant pain she had to undergo further minor surgery at home in April to remove a small piece of bone left behind during the first operation, only for a bacterial infection to then jeopardise her recovery. Vlasic is the double world indoor champion and reigning Olympic silver medallist. She won the silver medal at the world athletics championships in September.