Thorsten Engelmann has become the first Cambridge oarsman in modern times not to be awarded a 'Blue' despite helping his university to Boat Race victory.
Engelmann was in the losing Light Blues boat in 2006
He breached rules aimed at ensuring rowers selected for the world-famous event are genuine students who intend to complete their studies.
The German left during the second year of his three-year economics degree.
"It is our job to protect the integrity of the Race," said Giles Vardey, chairman of the Boat Race Company Ltd.
"The organisers of the Boat Race and the University Boat Clubs are guardians of one of the greatest amateur sporting events in the world.
"We all view very seriously any behaviour that is inconsistent with Boat Race traditions."
A 'Blue' is the recognition that each competitor receives for representing Oxford or Cambridge against the other university.
After leaving his course, Engelmann's name was not put forward to Cambridge University's Blues Committee.
He became the heaviest rower in Boat Race history when he tipped the scales at 17st 6lbs in April.
Engelmann is now part of the German national squad who have a home-based World Championships this summer in Munich which doubles as the Olympic qualifier for Beijing 2008.