LONDON, April 3 (Reuters) - Mercedes team boss Toto Wolff has backed Sauber's German driver Pascal Wehrlein to "come back strong" after having to miss the opening race of the season in Australia due to fitness issues.
Wehrlein, a Mercedes-backed driver who raced for now-defunct Manor last year, was withdrawn by Sauber for the March 26 Melbourne race and replaced by Italian Antonio Giovinazzi.
The Swiss-based Formula One team have yet to say who will compete in China this weekend.
"I feel for Pascal, because he has had all the bad luck," Wolff said in a Mercedes team statement on Monday ahead of the second round of the season in Shanghai.
"I'm impressed with the maturity he has shown to inform Sauber that he wouldn't be able to perform at the level required in Melbourne. That took courage and selflessness, which I know earned him a lot of credit within the team.
"Now, he needs to build up his fitness and come back strong. I have no doubt that when he's back in the car, he'll prove he's still the same Pascal."
Wehrlein injured his back in a crash at the Race of Champions in Miami in January, and took time off to recover.
He tested in Spain in March, and was cleared to drive at Albert Park before pulling out on the Saturday before final practice.
"My fitness level is not as it should be for a full race distance because of my training deficit," the 22-year-old said then in a team statement.
"Therefore, the Sauber F1 Team has decided not to take any risks. It is a pity, but the best decision for the team."
This year's cars are taking corners much faster due to fatter tyres and aerodynamic changes, subjecting the drivers to greater G-forces. Several drivers have worked hard over the winter to add upper body strength as a result. (Reporting by Alan Baldwin; editing by Mark Heinrich)