“We do however recognise the chance to take on the role of Technical Director within a Formula 1 team is an appealing next step in his career.”
Asked about the move in a press conference ahead of this weekend’s Styrian Grand Prix, Horner added: “All credit to Dan to be selected to be their technical director. He’s a great guy and has been a valued member of our team.
“Of course, we have tremendous strength and depth in the aero dept under Adrian’s tutelage. we have tremendous talent and it frees up an opportunity for the next generation.
“Dan will be here for a while. He’s focused on this year’s car and will be here until the end of his contract.”
Asked how long Fallows’ contract had left to run, Horner said that he would not be leaving for at least two years.
Fallows has tried to take flight from Red Bull before, after being wooed by McLaren into taking a role at Woking in 2014.
However, it appeared he had a change of heart, returning to Red Bull after a period of leave to take up the Head of Aero there, with Peter Prodromou then going to McLaren instead.