Lewis Hamilton is set to start the Italian Grand Prix at the back of the grid as Mercedes will use a fourth power unit of the season.
The seven-time world champion sustained damage to the power unit in the recent Belgian Grand Prix, where a collision with Fernando Alonso launched Hamilton's car into the air and led to his retirement shortly after.
Formula One regulations permit the use of three different power units over the course of a season and a grid penalty is issued to those who require the use of additional units – which takes the car to the back of the grid.
A Mercedes spokesperson told GPFans: "We will be fitting PU number [four] for this weekend for Lewis.
"This is because although we are still working on the recovery plan for PU number three that was damaged in Spa, that unit cannot be run this weekend.
"This will come with associated grid penalties as it's in excess of the allocation for the season."
Hamilton is not expected to be the only man on the grid to encounter a penalty for this weekend, with it reported former team-mate Valtteri Bottas will also take a fourth power unit in his Alfa Romeo.
The recent race in Belgium saw a number of engine penalties issued, including those to championship leader Max Verstappen and Ferrari's Charles Leclerc.