A number of drivers, including Fernando Alonso, have been linked with Rosberg's vacated seat but Mercedes junior Wehrlein is so far being considered the favourite.
"Pascal is a huge hope for Germany for the future," Rosberg said of his compatriot. "Of course he has to be on the shortlist."
But the 31-year-old said he does not want to play an active part in choosing his successor
"I am not best able to judge this," Rosberg said.
And when pressed by Italy's Autosprint to say who should replace him, Rosberg said: "I hope a good driver who makes a good fight with (Lewis) Hamilton."
Bahrain International Circuit - Winter testing