Toto Wolff says Pascal Wehrlein will stay with the Mercedes family as the German looks set to miss out on a drive in Formula 1 this season.
The Mercedes protege lost his Sauber seat to Formula 2 champion Charles Leclerc and is not in the frame to get the last vacant seat at Williams.
Instead he is weighing up a return to the DTM, where he was champion in 2015 before graduating to F1 with the now-defunct Manor team the following year.
However, Mercedes team principal Wolff has publicly backed Wehrlein's ability and confirmed that he will stay with Mercedes.
"Pascal definitely deserves a place in Formula 1 and is certainly one of the fastest drivers," Wolff told Motorsport.com.
"At the moment it looks a little bit bitter as far as the available [race] driver seats are concerned.
"But he's definitely going to be on our team. [It is unclear] whether or not he actively participates in a racing series other than Formula 1. He will definitely remain part of our squad."
Wehrlein scored all five of Sauber's 2017 points, courtesy of eighth in the Spanish Grand Prix and 10th in Azerbaijan.
But with Sauber's enhanced relationship with Ferrari and its new Alfa Romeo tie-up, there was no longer a seat available for the German.
Wehrlein suggested his best race performances of 2017 were overlooked because Sauber was so far behind by then.
"I'm quite happy in the end with five points," he said. "Not all of the races have been good as I wished but I think in general we did what we could do."
He added he not give up on trying to return to a race seat in 2019, when a shake-up of the grid is expected.