Carlos Sainz, Lewis Hamilton, Fernando Alonso and Kimi Antonelli have all been moved off the grid after their teams made overnight adjustments that triggered pit lane starts under Formula 1’s parc fermé regulations.

Sainz, who qualified 15th for Williams, will not take up his original grid spot after the team opted to change both the mechanical and aerodynamic setup of his car.

Hamilton, Alonso and Antonelli — who originally qualified 16th, 19th and 18th respectively — will also start from the pit lane after taking on new power unit components.

The updated elements exceed their seasonal allocation, but with low grid positions, their teams used the opportunity to boost engine resources for the rest of the season.

As per FIA procedure, the order of pit lane starters is based on qualifying position. Sainz will lead the group, followed by Hamilton, Antonelli and Alonso.

The reshuffle promotes Franco Colapinto to 15th on the grid and Lance Stroll to 16th, despite the Canadian setting the slowest time in qualifying.

Conditions at Spa-Francorchamps remain unpredictable, with heavy rain earlier in the day giving way to drier skies in the lead-up to the race.

However forecasts suggest further showers could arrive before the 3pm local start time (11pm AEST), setting up the potential for a dramatic race.

Lando Norris starts the race from pole, ahead of teammate Oscar Piastri and the Ferrari of Charles Leclerc.