Weil der Stadt, Germany - Former cycling professional Jan Ullrich said Friday that he believes seven-time Tour de France winner Lance Armstrong could win another title.

The 37-year-old American announced a short while ago that he was coming out of retirement to join the Astana team and compete in next year's Tour de France.

Ullrich, who won the Tour in 1997 said he also supported Armstrong in his refusal to allow a urine sample from 1999 to be examined for the blood doping agent EPO.

"Why should he do something that he does not have to do? I would also not allow that to happen. It is a matter of principle," the 34- year-old German said.

Ullrich, who has also had accusations of doping levelled against him and no longer races, is participating in a charity race.

He said that he could not believe it when he heard that Armstrong was attempting a comeback. "But I think it is a good thing. Lance is drawing the world's attention to cycling."

Ullrich, who currently lives in Switzerland, thrice finished second behind Armstrong in the Tour.

"I think he could win the Tour again. He has a great life and great women, but that is not his calling. He has that in his sport. If he manages the challenge mentally, his body will also be up to it," he said.

He said he believed Armstrong to be disappointed that the sport attracted most of its attention because of doping. "Through him the sporting aspect will become more important again."

Ullrich said he was not thinking of staging a comeback: "This option does not exist."

Ullrich, who has constantly denied doping, was pulled from the Tour in 2006 by his team at the time, T-Mobile, after he had been accused of doping. He retired a year later.

"I stopped riding under different circumstances than Lance. I suffered a lot of injustice and would only think about coming out of retirement if the same thing would not happen again. But at the moment I can't see that."