London: Mercedes boss Toto Wolff has vowed to make a brave decision as he looks to replace world champion Nico Rosberg.
Rosberg stunned the world of Formula One when he retired just five days after winning this year's drivers' championship.
Wolff has been working overtime to line up a new driver to race alongside Mercedes star Lewis Hamilton next season and, with pre-season testing due to start in February, he wants the situation sorted out as soon as possible.
Two-time world champion Fernando Alonso, entering the final year of his three-year deal with McLaren, has been linked with Mercedes.
Williams' Valtteri Bottas is another reported contender, but Wolff may decide to take a gamble on 22-year-old former Mercedes test driver Pascal Wehrlein.
"Clearly, with Nico taking the decision quite late we are in a bit of a compromised situation because if we had known three months ago there were more options available," Wolff told Sky Sports F1 on Friday.
"Maybe we need to make a brave decision in the same way Nico has made a brave decision."
Wehrlein graduated from Mercedes young driver programme and notched up Manor's only point of the season to underline his potential.
However, he was ignored for a Force India seat in favour of fellow Mercedes junior Esteban Ocon and is currently without a team for next year.
"Sometimes in life things turn out differently than you expected," Wolff said.
"I think in terms of performance, both have had great races in the past, had solid performances with Manor, and they deserve a future in Formula 1.
"Therefore I consider both of them as future stars."
Whoever steps in for Rosberg will have big shoes to fill and Wolff admitted his unexpected departure was a big blow.
"He will leave a very big gap because he was not only a very fast driver, but he was able to push Lewis," Wolff said.
"They pushed each other and were therefore really able to perform well and score our goals for victories.
"His technical ability in giving us directions and being part of the development work of the car, that's a part we are going to greatly miss.
"Whoever is going to replace Nico needs to fill those big shoes."