Pascal Wehrlein will sit out the rest of the 2017 season opener in Australia.
The German got FIA medical clearance to participate in Friday practice following his winter back injury.
However, Sauber announced early on Saturday that they have "decided to replace" the 22-year-old for qualifying and the race with Ferrari reserve Antonio Giovinazzi.
"My fitness level is not as it should be for a full race distance because of my training deficit," Wehrlein said.
Team boss Monisha Kaltenborn said: "We have great respect of Pascal's openness and professionalism. This decision was definitely not an easy one for him."
She added that Wehrlein will travel to China in two weeks.
