Needing another engine in Belgium on Friday, Sebastian Vettel says it's only a matter of time before he is hit with an engine penalty.
The Red Bull driver sat out the second of Friday's two practice sessions due to his car requiring a power unit change.
That meant Vettel managed just 11 laps on Friday with the German admitting that puts him on the back foot a bit.
He said: "It didn't help to collect any experience today. Obviously I didn't drive much, except a few laps this morning.
"Other than that, we saw that it is not the best circuit for us. We lacked speed down the straights, they are quite long straights here so we will see what we can do tomorrow.
"I think obviously there are a lot of boxes to be ticked in general, and it is important around here to get your eye in."
Vettel's concerns, though, stretch beyond just this weekend's outcome.
With drivers permitted to use only five 1.6 litre turbocharged V6 engines for the entire season, he fears penalties could be coming.
"The question is how many," he said.
He is, however, hoping that whatever went wrong on Friday is an easy fix.
"Hopefully the engine is not damaged. That is why we did not run - to check it."
Vettel's tally ahead of Friday's practice was four for his internal combustion engine, turbo charge, motor generator and control electronics.