Team Sky and senior directeur sportif Scott Sunderland have issued a joint statement confirming that they will immediately end their working relationship.
Sunderland says he has decided to spend more time with his wife Sabine, and two young sons Tristan and Saën.
Sunderland was one of the first people to join the team's management last year and played a fundamental role in selecting and signing many of the riders. He was in charge of the team during the Spring Classics in April but has recently been on holiday and was not with Team Sky at the Giro d'Italia.
"After spending many rewarding months working on the assembling and directing of a great group of people, this decision was made after careful consideration," Sunderland said in a statement.
"My wife Sabine and I have had many long conversations over the last few months and we agree that the wellbeing of our family and in particular the health of our youngest son Tristan asks for me to increase the time and attention I give to my loved ones. Our oldest son Saën has wholeheartedly welcomed this initiative."
"The fact that I am taking a step away from my responsibilities as Senior Sports Director for Team Sky does not mean that I will take distance from cycling; this sport has been and will always be an integral part of my life."
Dave Brailsford, Team Principal for Team Sky, said: “We would like to thank Scott for his contribution to Team Sky. He helped us get from the drawing board to being a real road team, working with us from the announcement of the project to our first podium finishes. We all wish Scott the very best, personally and for his future career.”
Sunderland added: “It has been an incredible journey, helping to set up a new, highly professional team from scratch. I’m proud of the team’s achievements so far and wish them the best of luck for the rest of the season, their first Tour de France and a successful future.”
Sunderland was one of four Sports Directors in the new professional road team, alongside Sean Yates, Steven de Jongh and Marcus Ljungqvist.
He comes from Inverell in Northern New South Wales and raced as a professional from 1990 until 2004. He won eight races during his career and fought back from serious injury when he was hit by a team car during the 1998 Amstel Gold Race.
He became a directeur sportif with Bjarne Riis' CSC team in 2005 and played a key role in the team's victories at Paris-Roubaix and when Carlos Sastre won the 2008 Tour de France.