Kingston: Jamaican sprint superstar Usain Bolt on Monday said the possibility of losing a gold medal is "heartbreaking", as his 4X100 metres relay teammate Nesta Carter is said to have tested positive for a banned substance during the 2008 Beijing Olympics. Carter, who helped the 4×100 team to Olympic and world championship titles, is said to have tested positive for the banned stimulant methylhexanamine during re-testing where 454 samples from the Beijing Games were used. "I'm not too pleased about the situation. For years, you've worked hard to accumulate gold medals and you work hard to be a champion, so it's heartbreaking, but it's one of those things," Bolt was quoted as saying by the BBC on Sunday. "If I have to give back my gold medal, I'll have to give it back," said the present World and Olympic champion. The 29-year-old spoke after he notched the 9.88 seconds mark which is the second fastest 100m time of the year. Carter has yet to comment on the issue. He was the first one to run for his country in Beijing followed by Michael Frater, Asafa Powell and Bolt. They had then recorded a world-record timing of 37.10 seconds.