Mercedes say Lewis Hamilton is "likely" to suffer a grid penalty for using too many engine parts at this weekend's Belgian Grand Prix.
The team say they will know for certain on Thursday, but a decision to take the extra engine parts Hamilton needs would mean a drop of at least 20 grid places.
A series of failures early in the season meant that Hamilton used up more engine components than planned.
He heads into the race 19 championship points ahead of team-mate Nico Rosberg.
Six wins in the past seven races for Hamilton have turned around what had been a 43-point advantage for the German after the first four races of the season.
A spokesman said the team were still working through the requirements and consequences related to any decision to take the penalty in Belgium.
The other option is to wait until the Italian Grand Prix the following weekend.
What did Hamilton do?
Drivers are allowed to use a maximum of five of each of the six parts of an engine before a grid penalty is incurred.
Hamilton has already used the maximum permitted five items of two elements of the complicated turbo hybrid engine - the turbocharger and the MGU-H, the electric motor that recovers energy from the turbo.
Teams are given a 10-place grid penalty each time they use a sixth example of any component, so using one new of each of these means a 20-place grid penalty for Hamilton.
There are only 22 cars on the grid and a driver can only go to the back no matter how many theoretical grid penalties he suffers for using additional engine components.
So Mercedes may choose to take two new examples of each of these parts to bring them into line with the number of the other parts of the engine he has used.
Hamilton has so far used three each of the internal combustion engine, MGU-K, energy store and control electronics.
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