Tom Boonen faces a fitness battle ahead of the Olympic Games after abandoning the Tour of Poland with a fractured rib.

Boonen, whose winning spree at the Spring Classics earlier this season included victories at the Tour of Flanders and Paris-Roubaix, was set to start the Olympic road race among the favourites.

The Classics-style course, which takes in nine laps of a hilly Box Hill circuit, suits a rider in Boonen’s mould but, having skipped the Tour de France to focus on the Games, the 31-year-old crashed on stage one of the Tour of Poland before eventually abandoning the race during stage five.

Boonen is expected to take three days rest before undergoing a medical assessment to decide whether the Belgian national champion is fit to ride the five-day Tour de la Region Wallonie.

“The entire day was OK, a little bit painful but OK,” said Boonen. “I worked for the team without particular problems. Then in the final, at about 30km from the finish, I did a wrong movement to avoid a pothole in the road, and suddenly I got really bad pain on the right side of my chest. I couldn’t breathe. That’s why I decided to stop.

“It’s a pity — my condition is good and here the team is fantastic, there is a great atmosphere. It’s hard to leave the team here, but I have to do what is best for my health leading up to the Olympics.”