Helmut Marko has confirmed Nyck de Vries has been warned to improve his AlphaTauri form after a sluggish start to the year but insisted a change of driver would not hand Daniel Ricciardo or Mick Schumacher a route back into Formula 1.
De Vries was awarded the second seat for Red Bull's junior team over the summer after scoring points on his surprise F1 debut with Williams last season. However, the rookie has struggled to impress and remains pointless after his first five races.
As a result, speculation over an early axing has mounted, with De Vries undoubtedly already fighting for his future in the sport. His cause has not been aided, either, by the current availability of Ricciardo, Red Bull's reserve driver.
Marko, though, looked to wave off the links to the former McLaren man after laying down the gauntlet to De Vries and urging him to lift his levels moving forward.
"Nothing will happen in the next three races," he told F1 Insider. "We spoke to De Vries and he agrees with us: he needs to improve.
"The distance to teammate Yuki Tsunoda, who is doing a great job, is too big. To use footballer jargon, Nick got the yellow card, but not the red yet. If he improves, a driver change will not be an issue."
Marko then revealed that Red Bull would decide to delve back into their junior ranks to replace De Vries, with the highly-rated Liam Lawson in contention.
"If the worst came to the worst, we would fall back on our pool of young talent," Marko added. "It's specifically about Liam Lawson and Ayumu Iwasa.
"Ricciardo is not an issue."
Schumacher, the son of all-time great Michael, will also not make the potential shortlist. "He's a Mercedes driver and he's not in our plans," Marko said. "Accordingly, [team principal] Toto Wolff is responsible for him."
According to Motorsport.com, Marko's ultimatum to De Vries has seen him handed three races to improve or risk being abruptly replaced mid-season.
The calendar takes the action to Italy, Monaco and Spain over the coming weeks.