Asked whether he would consider it, and on the prospect of going up against Max Verstappen, Vettel replied: "Generally I'm of the conviction that if you want to win you have to be happy to take on anyone.
"I obviously know the team very well from my past, so of course, I am still in contact with a lot of people there, whether it's Christian [Horner], Helmut, or others.
"Red Bull has a winning car, I believe so. They are a very strong team, I know how strong they are from the past. Obviously, a part of the team is not the same and they have evolved, so it's not fair to say I know the team inside out because it also has changed and moved on.
"But I know why they were strong back then, and they are still a contender, and obviously, it's a car you can win races in, so for sure, that would be interesting."
Asked directly if offered a drive with the Red Bull team whether he would take it, Vettel said: "It's a winning car, and as I said earlier, I am here to compete, to win - so probably the answer would be yes."
Intriguingly, Vettel was effusive in his praise for Racing Point, that next season morphs into Aston Martin, and a car that has clearly proven this season after the weekend's opening race in Austria that its pre-season testing form was no flash in the pan.
"I think Racing Point left a very strong impression and are certainly in a good place for this year," added Vettel.
"I know part of the team, I know some members of the team quite well from my past and for a long time, so I think obviously it's a good opportunity for them this year to have a good car to fight with and try to improve from there."
Vettel, though, insists that "everything is an option at the moment", which includes the possibility of leaving F1 or taking a sabbatical, as suggested by Marko, but he has yet to make a decision.
Perhaps unsurprisingly, Vettel did discuss with Renault its vacancy prior to the team opting for Alonso.
"I've spent such a long time in the paddock that I know quite a lot of people, so yes I did [have talks], but obviously at no point concrete enough or fundamental talks or real talks," said Vettel.
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