Team Sky performance director Rod Ellingworth will leave to join Bahrain-Merida from next season, ending a decade-long association with the British squad.
The 46-year-old former British Cycling coach has been with Team Sky - who will be relaunched as Team INEOS next month - since the team's formation in 2010, and has worked with riders such as Geraint Thomas and Mark Cavendish since their youth.
A Team Sky statement said Ellingworth told senior management of his decision earlier this season.
"He will remain with the team for the immediate future to ensure an amicable and smooth transition," the statement said.
"Everyone at the team thanks Rod for his immense service and contribution during his time with us."
The ambitious Bahrain-Merida squad went into partnership with McLaren at the start of the season, with the motorsports company expected to step up its involvement in the team in 2020.
Ellingworth has been a key part of five Tour de France victories with Team Sky, and was also the manager of British Cycling's men's elite road team until last year.