Sauber plans to run the new Ferrari-spec Formula 1 engine at next weekend's Spanish Grand Prix, Autosport has learned.
Ferrari spent three tokens as part of an upgrade that it introduced for its works team at the Russian GP.
Customer Sauber will now receive the same spec and it has decided to use it immediately.
As a result, Felipe Nasr and Marcus Ericsson will move onto the second of their five allocated internal combustion engines.
The move provides a boost to the team as it is struggling financially and will not introduce any aerodynamic updates for the Spanish GP.
It will also miss the first in-season test, which takes place at Barcelona on the Tuesday and Wednesday after the race.
The same engine spec has been offered to fellow customer Haas but the American team has yet to decide whether it will introduce it in Spain.
Ferrari's third and final customer Toro Rosso will not get the new upgrade as its deal is to use the 2015 spec.