Contador a diamond to be polished - Astana chief

Alberto Contador is a diamond that still needs a bit of polishing, Astana sports director Alain Gallopin said.

The Spaniard, one of only five men with all three big races (Tour de France, Giro d'Italia and Vuelta a Espana) to his name, is one of the best riders in stage races, yet he is not sure to be Astana's leader in July.

The 26-year-old, who won the Tour in 2007 and claimed a rare Giro/Vuelta double last year, is in competition with seven-times Tour champion Lance Armstrong, back this season from three and a half years in retirement.

"He is a young leader, he still has to learn," Gallopin said.

"But having a 25, 26-year-old rider able to be a team leader on the big tours is rare, especially at this level."

Contador, who leads the Astana team on the Paris-Nice, was caught off guard when the Rabobank team blasted the peloton open with a violent attack on Tuesday and lost more than a minute.

"He still makes young leaders' errors," said Gallopin.

"These are mistakes an old leader would not make. But I prefer him to make this kind of mistake on the Paris-Nice rather than during the Tour de France."

Gallopin, however, believes that Contador needs some freedom on a race to give his best, and that the Spaniard will be ready for the Tour starting on July 4 in Monaco.