Other team's drivers are not off-limits, though, and recently Marko suggested that a driver from Red Bull's biggest rivals this season - McLaren - was indirectly attempting to join the team.
Oscar Piastri was the driver in question, with Marko claiming that his manager and former Red Bull driver Mark Webber was 'intensively seeking conversation'.
Naturally, Piastri was quizzed about these comments at the Mexican Grand Prix this past weekend, but it does not appear as though he will be joining Red Bull any time soon.
“I think we all know that Helmut says a lot of things in the press," Piastri told the media.
"As far as I’m aware there’s no truth to it."
Piastri went on to reveal that he is very much happy where he is at present having been treated well by McLaren since joining the sport.
“I’m very, very happy where I am,” the McLaren star added.
“The team have supported me massively since I came into F1, they gave me my opportunity in F1.
"At the moment in the standings, we’re in a very happy place, so I am more than happy with where I am at the moment.”