"I'm very sorry, but I won't be racing in the Tour de France this year," the German said yesterday at the Freiburg University clinic where he is having treatment.
Ullrich was forced out of the Tour of Switzerland with a sore right knee last Wednesday. He first received the injury in a crash during the Tour of Germany on May 30.
After dropping out of the Swiss race, Ullrich's chances of contesting the Tour de France were considered slim.
"The first problem to tackle is getting my health back." Ullrich said, adding he did not know when he would race again. He declined to comment on recent allegations made by German magazine Der Spiegel that his Team Telekom engaged in systematic doping.
Both the team and their sponsor deny the allegations and have started legal action against the magazine.
In Meiringen, Russia's Viacheslav Ekimov roared to victory in the sixth stage time-trial of the Tour of Switzerland as Frenchman Laurent Jalabert reclaimed the overall lead.
Ekimov powered his way around the undulating 29.5km circuit in 36min 10sec, 34sec clear of Steffen Wesemann. The German was the only rider to come within a minute of Ekimov. Slovenian Martin Hvastjia was third, 1min behind.
Jalabert, who surrendered the overall lead to Gilberto Simoni and trailed the Italian by 25sec after Saturday's gruelling mountain stage, reclaimed the yellow jersey by a slender two seconds when he finished yesterday's stage 1min 22sec behind the winner.
It was the first time in four time trials in Switzerland this season that the world number one Frenchman had failed to produce a win.
With more mountain stages ahead, Jalabert is two seconds ahead of Simoni, a dangerous climber, who finished third in the Giro d'Italia and second in the Tour of Trento.Reuse content