The South Korea international is turning out in the K-League at present for Chunnam Dragons, but is closing on a switch to England.
It is claimed that the 22-year-old defender will leave his team's training camp on Thursday to undergo a medical in London.
Yun has turned out in England before, as he graced the 2012 Olympic Games with his national side.
He has since gone on to make his international bow at senior level, with South Korea taking aim at the 2014 World Cup.
It is possible that he could be a QPR player by the time that tournament rolls around, with Yun all set to become the latest Korean to grace the English top flight.
"He is expected to sign a contract with the QPR if he passes the test," read a short statement released by Chunnam Dragons.