Red Bull duo Daniel Ricciardo and Max Verstappen have been given grid penalties at the Italian Grand Prix along with Fernando Alonso and Carlos Sainz for having new power unit components fitted.
Ricciardo finished third in the Belgian Grand Prix last weekend, but will have to produce something special to secure another podium finish at Monza on Sunday.
The Australian was given a 20-place penalty after a fifth engine and turbo and a sixth MGU-H of the year was applied to his car - only four of any element are allowed in a season.
Verstappen retired for the sixth time this season at Spa-Francorchamps last Sunday due to early engine problems and has been hit with a 15-place relegation following the fitting of a fifth ICE and MGU-H.
Alonso will start at the back of the grid again as a result of a 35-place penalty after McLaren made a seventh engine change and several other alternations to the Spaniard's car.
Sainz will take a 10-place demotion for a fifth MGU-H on the Renault power unit of his Toro Rosso.