Various handling issues through the opening three races have hamstrung Sauber’s Felipe Nasr, who’s yet to finish better than 14th this season.
He’ll come to Russia with a new chassis, confirming the switch during the FIA Press Conference on Thursday.
“I can confirm I get a new chassis here,” Nasr told reporters in Sochi. “Although F1 cars are made of many components and the chassis is just one part, I think it is a sensible step from the team that we are looking further to discover these handling problems and issues I am having in the car.
“Since we put the car on track in Australia we’ve been having this very strange behavior – let’s say it’s very unpredictable to drive the car.”
Nasr finished sixth in Russia last year in a race of high attrition, then was ninth at Circuit of The Americas later in October. He got caught up in a first turn collision with Lewis Hamilton last race at China.
Sauber has not scored as a team since Austin, with Marcus Ericsson also riding a 10-race scoreless drought since finishing ninth at the Italian Grand Prix.