Armstrong won seven straight Tour de France titles between 1999 and 2005

Lance Armstrong may have to accept a supporting role to Astana team-mate Alberto Contador in next year's Tour de France, according to his team boss.

Astana cycling director Johan Bruyneel says Contador, the 2007 Tour de France winner, will not be leaving the team.

"Alberto is the best professional cyclist in the world," he said. "The strongest rider will be supported."

Meanwhile, Armstrong has rejected a call to re-test urine samples from his first Tour win for the drug EPO.

Pierre Bordry, the president of France's anti-doping agency, said Armstrong should have his first Tour de France win sample in 1999 tested for the blood-boosting drug.

But Armstrong said: "Mr Bordry is new to these issues and his proposal is based on misunderstanding the facts.

606: DEBATE I'm still trying to get my head around the reasons for Armstrong's return SOBorSOG

Armstrong won seven Tours in a row before retiring in 2005, but is hoping to make a comeback to the sport in January with Astana.

Contador let it be known he would quit the team if he was given the role of supporting Armstrong, but Bruyneel says the Spaniard will not be allowed to leave.

"At the end of the day, the strongest rider will be supported, regardless of that person's name or what they've accomplished in the past," said Bruyneel.

"Lance must prove that he has the physical ability to win big races.

"This is not the first time that big names have all been on the same team. It has worked out in the past and I'm confident for the same in 2009.

"As for Alberto, he signed a contract with Team Astana until 2010, I have invested a lot of my time into Alberto's development and he will remain with this team for the next two years.

"Actually it's pretty simple, there's a contract and there are no options to leave."