Kiwi Brendon Hartley and Toro Rosso teammate Pierre Gasly are likely to take grid penalties at this weekend's Brazilian Grand Prix.
The Renault-powered team suffered multiple engine failures across the Mexican Grand Prix weekend a fortnight ago and will almost certainly need power unit replacements in both cars.
Hartley's situation is more obvious - his car blew up and caught on fire midway through the Mexican Grand Prix so he is certain to attract a grid penalty.
Gasly managed to finish in Mexico but he admitted there was a strong chance he would start off the back of the grid upon arriving in Brazil.
"It is not confirmed yet, but it looks like it," the Frenchman told Motorsport.com.
"It looks like we will have to start from the back of the grid, which makes it of course pretty difficult. But it is something that we cannot really change.
"We have to accept it if we take it. But it doesn't change the target in the end, it just makes it a bit tougher."
Hartley talked about wanting to finish inside the top 10 and earning a championship point as his goal for the event but starting near or at the back of the grid will seriously hurt those chances.
Practice at the Interlagos circuit begins tomorrow morning before qualifying on Sunday and the race on Monday morning.