The German injured his back in a crash at the Race of Champions in Miami in January and was replaced by Giovinazzi for the first winter test in Barcelona.
Wehrlein returned for the second test and was cleared this week to drive in the season-opening race at Albert Park but withdrew before free practice on Saturday.
“My fitness level is not as it should be for a full race distance because of my training deficit," Wehrlein said in a team statement.
"I explained the situation to the team yesterday evening. Therefore, the Sauber F1 Team has decided not to take any risks. It is a pity, but the best decision for the team.”
(Reporting by Ian Ransom; Editing by Peter Rutherford)
Share
