At one of his last training sessions before the European Championships Munich, which start on August 11, Heß fell unhappily on the shoulder as well as acquired his damaged collarbone.
As the German Athletics Association announced on Tuesday, the Chemnitzer will certainly be terminated for several weeks after a required procedure.
This is especially bitter because he was actually going again, claimed his instructor Harry Marusch.
Hess won in 2016 with a size of 17.20 meters EM gold in Amsterdam.
At the Globe Championships in Eugene (U.S.A.) at the end of July, the 26-year-old of LAC Erdgas Chemnitz missed out on the final of four centimeters as the 13th of the pre-fight.