Germany's Auto Motor und Sport said championship leader Sebastian Vettel is worried the grooves might disadvantage those who qualify best for the Belgian grand prix.
"There is probably a disadvantage for the start, because you will have less tyre on the track," said the German.
Correspondent Michael Schmidt asked F1 race director Charlie Whiting for an explanation.
"In this area we needed better drainage for when it rains," he said.
"We have good experience with this method from Brazil," added Whiting.
He said he is not concerned that the upper half of the grid will face grip problems on Sunday afternoon.