As Toto Wolff was campaigning for the 23-year-old to be considered by Williams, he warned that Mercedes cannot financially prop up the German's place in Formula 1 forever.
Yet after Wehrlein lost his Sauber seat to Ferrari junior Charles Leclerc for 2018, Wolff now says thatMercedes will keep backing the 2015 DTM title winner.
"Pascal definitely deserves a place in Formula 1," Wolff is quoted as saying by Italy's Autosprint. "He is among the fastest drivers.
"At the moment things seem a little difficult regarding the available seats, but he will absolutely remain in our team."
However, an exact role for Wehrlein within the Mercedes programme is yet to be announced.
"It is not clear if he will race in a category outside Formula 1, but what is certain is that he will remain part of our team," Wolff added.
The man who decided to oust Wehrlein - new Sauber chief Frederic Vasseur - admitted that it is tough for some of F1's younger drivers to make their way in the category.
"Even if a newcomer is very competitive it is not easy for him," the Frenchman is quoted as saying by Auto Hebdo.
"This is evident in Mercedes and Ferrari, who do not risk putting their drivers [Esteban] Ocon or Leclerc in their cars because the stakes are too high.
"Instead they give their drivers experience in partner teams. The top teams do not feel confident in their young drivers."
The 2018 championship begins with the Australian Grand Prix on March 25.