Vettel won his four consecutive championships with Red Bull between 2010 and 2013 and came close to winning further titles with Ferrari after he joined the Maranello squad in 2015.
With the driver market being in utter chaos heading into 2025 and numerous seats currently available, the German has been linked with a possible return to the sport.
Marko: Vettel has repeatedly enquired about Red Bull
Now, according to Marko, the 36-year-old has been enquiring about returning to the Milton Keynes-based squad and replacing Sergio Perez.
Speaking with Formel1.de, the 81-year-old Austrian said: “Vettel has repeatedly enquired with us, but I don’t think it would be pleasant for him to drive next to Max Verstappen.”
Since 2018, the Dutchman’s previous team-mates in Daniel Ricciardo, Pierre Gasly, Alex Albon and now Perez have struggled to compete with him and it is likely to be no different if Vettel was to get the drive.
Furthermore, Red Bull recently announced a renewal of Perez's contract, ensuring he will remain with the team until 2026.
The German has remained connected to the motorsport world, having recently tested the Porsche 963 hypercar in Spain and hinted at a possible move to endurance racing.
“If I’m correctly informed, he seems to be moving towards Porsche and long-distance racing. I think that would be a very nice step for him,” added Marko.