Paris - Roubaix will be the final race of Sagan 's spring campaign .
Sagan will skip Amstel Gold Race before returning to action at the Tour of California as Sagan builds towards the Tour de France .
Paris - Roubaix will be the final race of Sagan 's spring campaign , and he will skip Amstel Gold Race before returning to action at the Tour of California as he builds towards the Tour de France .