Cavendish stood up after the crash but was taken to the Ghent University Hospital for observation --- his team, Deceuninck-Quick-Step, announced Monday he broke 2 ribs on his left side and a small pneumothorax.
"It is expected that Mark will be discharged either later today or tomorrow morning," Cavendish's team said, "and will then undergo a period of recuperation."
Cavendish -- in his hospital bed -- thanked all the fans for showing love via IG -- saying, "Just want to say how overwhelmed & thankful I am for all the support and well-wishes."
"In a bit of pain, but a couple of nights with the incredible staff here at Ghent University Hospital should sort me out."
Cavendish -- who won 34 Tour de France stages -- was just named, by the Tours' director, as one of the greatest sprinters in Tour history and cycling.