PARIS (AP) — Former world road champion Tom Boonen will undergo surgery on Wednesday after damaging his left shoulder and elbow in a crash during the Paris-Nice race.

The one-day classics specialist, who will miss the Tour of Flanders and Paris-Roubaix because of his injury, underwent medical tests that confirmed he suffered an acromioclavicular joint dislocation, and broke his radius bone.

Boonen retired from the Paris-Nice on Monday after colliding with teammate Nikolas Maes.

Boonen's Etixx-Quick-Step said in a statement that only his dislocated collarbone requires surgery, while his fracture will be treated with a cast.

No date for his return has been set, his team said.