Sauber's talks with Mercedes regarding a potential seat for Pascal Wehrlein have been put on hold while the German car manufacturer weighs up whether or not the German should join its works team next year.
Wehrlein has been eyeing a step up the grid for 2017 and, with Force India having opted for Esteban Ocon instead, one possibility was for him to join Sauber.
Mercedes had opened discussions with the Swiss team's chiefs regarding a deal to place him there for 2017, but speaking on Tuesday, the German car manufacturer's motorsport boss Toto Wolff admitted that the talks have had to stop for now.
Wehrlein is now the front-runner to make the step up to the Mercedes works teams in the wake of Nico Rosberg's shock retirement, although the outfit is aware that there is a risk taking such a youngster.
Speaking to German news agency DPA, Wolff said: "The talks between us and Sauber are at an advanced state. In the last couple of weeks I had good talks with them. But due to the new situation they are put on hold for the moment."
Wolff is a big supporter of Wehrlein, but is aware that it is not ideal asking him to face the pressure of a potential world championship campaign after just one full season in F1.
"Pascal is an ambitious young man," he said. "He has big aims and we share those aims. This is why he is part of our development programme.
"He's done a year with Manor. And if I could do a Christmas wish list I would wish for him to have another year or two at a midfield team. But there won't be a Christmas wish list for me this year.
"Therefore, we have to aim for a good compromise. And as Nico had to take a brave decision, maybe we have to take a brave decision as well."
Although Wolff told Sky earlier that Fernando Alonso was being considered, he has again expressed reluctance to get involved in a battle over contracts.
"Yes, we do respect contracts that other drivers have with other teams," he said. "Ourselves, we wouldn't want our drivers to turn their heads when a new opportunity arises. This is what contracts are there for and this we do respect.
"We don't want a situation in which we are having a confrontation or a legal battle. Of course, there's the possibility to come to terms with another team and driver if we were to find a suitable solution for both sides. I cannot exclude this possibility."
Additional reporting by Stefan Ehlen
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