Monisha Kaltenborn has questioned Sauber's decision to oust Pascal Wehrlein.
Earlier this year, the Swiss team parted with Kaltenborn and appointed Frederic Vasseur as their new boss.
Vasseur has since scrapped Kaltenborn's decision to switch to Honda power, and replaced German Wehrlein with Ferrari junior Charles Leclerc for 2018.
Kaltenborn has now told Auto Bild that although the Mercedes junior appears to be left without an F1 seat, Wehrlein is highly underrated.
"I think his performance in 2017 is still not properly appreciated," she said.
"Without him, the team would have scored no points at all.
"I just hope that he will continue to get what he deserves in Formula 1, which above all else is a cockpit.
"Pascal has the potential to become world champion with the right team. Anyone who has worked with him knows that."
Sauber finished bottom of the 2017 team rankings, picking up five points all season.
