This article was originally published on Cyclingnews.com.
The Belgian had new medical checks in the Herentals Clinic on Sunday.
Boonen crashed with around three kilometres left to race on Stage 1 of the Tour of Poland and continued several more days before abandoning.
It has now been confirmed that the 31-year-old is suffering from a fractured sixth rib on his right side. According to a team press release Boonen will now observe three days of rest before attempting to resume training on Thursday. A decision will then be made on wither the Belgian champion will race the Tour de la Region Wallone before the Olympic Games road race on July 28.
"There's nothing more to do than wait and see how the situation will evolve," said Boonen. "I'm sad because my condition is good and I really don't want to lose the chance to participate in the Olympics.
"On Thursday I will have the answer that I'm waiting for."
Boonen deliberately avoided racing both the Giro d'Italia and Tour de France, in the lead up to the Games, and recently admitted that it was also unlikely that he will ride the Vuelta a España prior to an attempt at a second world title to add to his 2005 crown.