British rider Jonathan Tiernan-Locke has been banned for two years and stripped of his 2012 Tour of Britain title for an anti-doping violation.
The International Cycling Union (UCI) imposed the suspension after finding discrepancies in the 29-year-old's biological passport.
Team Sky responded by terminating Tiernan-Locke's contract "with immediate effect".
He will be not be available to race again until 1 January, 2016.
The Plymouth-born rider pulled out of the 2013 Road World Championships in September after being asked to explain his results by the UCI, and has not raced since.
Team Sky say the anomalies arose in September 2012, shortly before he signed his two-year contract with the British team.
"In our team, there is no place for cheats," team principal Sir Dave Brailsford said.
"If he has been convicted, I presume it is because the UCI think he has cheated.
"Everybody who comes to Team Sky knows what our stance is. His contract has been terminated."
Team Sky rider Geraint Thomas backed Brailsford's actions, and expressed frustration that a British rider had broken the sport's anti-doping rules.
"It hurts more, for sure, with him being British," the BBC Sport columnist said.
"I would ban him if he has been cheating. There is no space for it at all."
Tiernan-Locke raced for Endura Racing in the 2012 season, claiming overall wins in the Tour Mediterraneen, Tour du Haut Var and Tour Alsace.
In September 2012, he became the first British rider since 1993 to win the Tour of Britain.
|Jonathan Tiernan-Locke factfile|
|1993: Takes up road racing at the age of 18 and joins a French amateur team|
|2005: Diagnosed with a virus which affects his immune system and forces him to stop racing for more than three years|
|2010: Returns to racing with Rapha Condor team and wins king of the mountain jersey in the Tour of Britain the following year|
|2012: Signs for Endura Racing, and goes on to win the Tour Mediterraneen, Tour du Haut Var, Tour Alsace and the Tour of Britain|
|October 2012: Joins Team Sky on a two-year deal|