Spanish cyclist Robert Heras has left Lance Armstrong's US Postal team to join new Spanish-based outfit Liberty.
Heras is a mountain specialist
His decision to quit the American team will be a major blow to Armstrong, who is bidding for a record sixth Tour de France crown next year.
"Roberto Heras has decided to sign with Liberty, the new team of Manolo Saiz," a statement by US Postal read.
The 29-year-old has been offered a three-year deal by Liberty thought to be worth around £850,000 a year.
The Spanish outfit will also have to pay US Postal a hefty fee to extract Heras from the remaining year of his contract.
US Postal team manager Johan Bruyneel had appeared resigned to
Bruyneel said on Wednesday: "Nobody is irreplaceable but we wouldn't like to lose him."
Heras also found himself in demand when he joined US Postal from the Kelme team at the beginning of 2001.
Following a bitter contractual battle he left the Spanish-based team after US Postal agreed to pay compensation.
Heras has been one of Lance Armstrong's most influential team-mates during the last three Tours.
He played a key role in shepherding the American through the mountains on his way to a fifth straight victory earlier this year.
Heras confirmed his status as one of the world's best
climbers with a brilliant performance on his way to victory in this year's Vuelta, and some believe he is one of the few riders capable of challenging Armstrong in the Tour.