The 30-year-old was put through his paces by the club on Monday ahead of a season loan move from Chinese club Shanghai SIPG.
According to getreading, the 30-year-old did not pass the medical checks as he would not be fit enough to play for eight weeks.
So the Championship club have opted against signing the former Sunderland man.
Gyan made his name in England playing for the Black Cats, who he joined from Rennes in 2010. He spent two seasons with the Black Cats before heading to Al Ain in Abu Dhabi where he scored a staggering 73 goals in 65 games – including 44 goals in one season.
Then in July 2015 he joined Chinese Super League team Shanghai SIPG – having secured a contract which made him one of the best paid players on the planet – taking home £227,000 a week.