Red Bull advisor Dr Helmut Marko has closed the door on an F1 return in the Red Bull family for Jean-Eric Vergne.
The Frenchman contested three seasons with Toro Rosso, Red Bull's junior team, from 2012 to 2014, scoring a best result of sixth place (Canada 2013, Singapore 2014).
Following his departure from F1, he joined the all-electric Formula E series, where he has since become a two-time world champion, picking up eight race wins and 19 podiums.
Red Bull has rotated its drivers a number of times in recent years, however any return for Vergne at the team has been ruled out by Marko, who thinks there would be too much to learn all over again.
"That book is closed. If a driver like Jean-Eric Vergne wins the Formula E, the profile with requirements is completely different from what we need in Formula 1," Marko told Motorsport-Total.com.
"He would be more or less a complete newcomer in that. It would take him a whole season to get used to the peculiarities of the Pirelli tires."
Marko pointed out that Red Bull has become more stringent with its choices over who to place in the junior team in recent years.
"We finance these people for one or two full seasons," Marko stated. "Without that support, they would not even get this chance.
"In the beginning, the junior team was only meant to support certain drivers, but now a talent must have the potential to win a Grand Prix. The selection is, therefore, stricter
In the pecking order of the junior programme, the next candidates that are hoping for a full-time race seat in F1 are Juri Vips and Yuki Tsunoda, who will race in Super Formula and Formula 2 respectively in 2020.