Valtteri Bottas is set to start the Belgian Grand Prix from the back of the grid after taking a new Mercedes power unit at Spa-Francorchamps. Lewis Hamilton has also taken on fresh components, but they are within his permitted limit for the season, so the Formula 1 championship leader's weekend will not be affected.
Renault's Nico Hulkenberg is set to join Bottas on the back row of the grid, as he has also taken on a fresh power unit in Spa - typically a scene of engine penalties in recent years as overtaking is easier on the seven-kilometre long circuit.
Williams and Force India will also be given new, upgraded power units by Mercedes, although it will not cause grid penalties for any of their drivers.
Bottas was facing penalties at some point in the second part of the season after a hydraulic failure in the Austrian Grand Prix caused that power unit to overheat.
Hamilton will take on a new internal combustion engine, turbo charger and MGU-H.
His title rival Sebastian Vettel will reportedly also take on a fresh power unit, adding a layer of intrigue to an already thrilling title race as attention turns to whether Ferrari or Mercedes have eked the most out of their new parts.