Sauber's only update for the Spanish Grand Prix is a new Ferrari engine specification, according to Felipe Nasr.
Most teams launch significant chassis and aerodynamic upgrades at the first European race of the season.
However, Nasr is quoted as saying by Brazil's UOL in Barcelona: "The only update we have this weekend comes from Ferrari."
The works team Ferrari used performance tokens to update its engines in Russia, and now customer Sauber will fit the new power units to its cars in Spain.
"On the aerodynamic side, we have nothing," Nasr admitted. "The others bring updates because, as it is the same track as testing, you can compare the improvement of your car really well here.
"The result of the Spanish Grand Prix usually ends up dictating what the European season will be like."
Even backmarker Manor has an update for Barcelona, causing Pascal Wehrlein to say this week that moving past Sauber is now the team's goal.
"That they were already close, yes, that was clear," Nasr acknowledged. "What we have to do is focus on our work. It may be that this update from Ferrari helps us a little.
"We will have to do what we can."
Sauber remain pointless so far in 2016.
