The former cyclist and current Team Sky coach Bobby Julich has left the British team after admitting taking a banned substance during his career as a professional rider.
The American, who retired from cycling in 2008, had been a coach at Team Sky since 2011.
In the wake of the Lance Armstrong doping scandal, Team Sky asked every member of the team to sign up to a written policy saying they have no past or present involvement with doping.
Julich has admitted using the blood-boosting agent EPO as a rider between 1996 and 1998.
Julich, a team-mate of his disgaced fellow Texan Lance Armstrong in 1995 and 1996, says he personally lost perspective of the gravity of the situation.