The announcement after medical examinations Tuesday immediately sparked speculation about his participation at the Tour de France in July, with the Bild daily asking on its Web site "Is the Tour in danger as well?"
T-Mobile said that Ullrich is suffering from an inflamed knee which makes him unable to kick off the season as planned at the Circuit de la Sarthe stage race in France which starts next Tuesday.
Instead, the 32-year-old will enter the season at the Tour de Romandie event in Switzerland April 25-30.
For now, Ullrich has been told by doctors that "it is impossible for him for medical reasons to compete in a cycling race" and that Ullrich can only do light training. Ullrich said he was "disappointed about the setback" while T-Mobile manager Olaf Ludwig said that "we must do everything to get the inflammation out of the knee as quickly as possible."
Ullrich's main event of the year is the Tour de France in July which he aims to win for the second time following the retirement of seven-time winner Lance Armstrong. Ullrich won the Tour in 1997.
However, the knee problems are seen as a setback as Ullrich will find it hard to make up for the lost weeks of hard training for the three-week race all his rivals will have gone through. The injury could also lead to the cancellation of Ullrich's planned start at the Giro d'Italia.
"Everything depends on how fast he regains his health," said Ludwig.