Renault works drivers Daniel Ricciardo and Nico Hulkenberg, as well as McLaren's Carlos Sainz, have returned to the manufacturer's older-spec unit for the remainder of the Belgian Grand Prix weekend.
Renault introduced its latest Spec-C engine at Spa, with Ricciardo, Hulkenberg and Sainz using the updated unit on Friday, which entailed a grid drop for Sunday's race for all three drivers.
While many speculated the switch-back had perhaps been done for reliability reasons, Renault insisted its decision was strategic and planned from the beginning.
Indeed, the move allows both Renault and McLaren to add the Spec-C unit to the teams' pool of engines at a venue where the effects of a grid drop are relatively minimized.
"The plan is to take penalties at a track where there is a possibility to overtake, while entering a needed extra ICE into our pool for the rest of the year," explained a Renault spokesperson.