Belarus hammer thrower Ivan Tsikhan will miss the London Olympics, the country's sports ministry said on Friday, after a request from athletics' world governing body.
"Tsikhan will not compete at London," ministry spokesman Vladimir Nesterovich told reporters. "Belarus athletics federation received a letter from the world athletics ruling body IAAF with a demand to sideline Tsikhan.
"The IAAF letter said that new methods of testing discovered the presence of banned medications in the samples, which Tsikhan gave at the Athens Games (in 2004) and 2005 World Championships.
"We decided to withdraw Tsikhan from the competitions to avoid any possibility of sanctions against the entire Belarus athletics squad at the Olympics."
In Beijing in 2008, Tsikhan won bronze but was later stripped of his medal by the International Olympic Committee (IOC) after tests showed too high levels of testosterone in his body.
However, in 2010 Tsikhan and his teammate Vadim Devyatovskiy, who was also stripped of his silver in Beijing for a doping offence, appealed against the IOC decision at the Court of Arbitration for Sport and won the case.
Nesterovich added that every single sample that Tsikhan gave for testing ahead of the 2012 Olympics were negative.
After stripping the two Belarussians of their medals, the IOC gave a life ban to Devyatovskiy and excluded Tsikahn from competing in London in line with a ruling that automatically bans an athlete caught doping at an Olympics from the next Games.
The CAS ruling ordered the IOC to reinstate both athletes' medals. Both are currently listed as silver and bronze medallists in the men's hammer competition at Beijing on the IOC website olympic.org.