Mercedes won't open talks with rival drivers until Nico Rosberg's future is clear, according to motorsport boss Toto Wolff.
The Mercedes team are currently negotiating with Rosberg – who has enlisted the help of Gerhard Berger – as the German's contract is set to expire at the end of the current season.
Whilst those talks are ongoing, Wolff says Mercedes won't listen to approaches from rival drivers.
"Right now our goal is to continue with Nico," he told Sport Bild. "We know that we have the strongest car, a very strong team and also for the future we are well positioned. That would be the main argument for Nico [to stay].
"If that doesn't come together, we have to think of something else."
When asked what he would say to Sebastian Vettel if he were interested in the currently vacant seat, Wolff replied: "I would tell him the same thing I've said to similar calibre [drivers]; First, we talk to our regular drivers. Only when we can not find an agreement with them, can we talk to others."
A vacant Mercedes seat would be hot property with several drivers likely to fight over the chance, but Wolff hinted that they could opt to promote from within instead, with Pascal Wehrlein an option for the future.
"Yes, absolutely [he's an option]," he added. "He has been in the DTM and proved how you win championships. At the moment he is learning at Manor but is on the right track to land [a drive] sometime at Mercedes."
