Tsunoda qualified 19th for AlphaTauri at Spa on Saturday after a scruffy final lap in Q1 meant he was unable to advance, although the litany of grid penalties for other drivers meant he was due to start from 13th today.
But AlphaTauri has now opted to fit some fresh power unit elements in Tsunoda’s car ahead of the race, taking a fresh engine, turbocharger, MGU-H, and MGU-K.
As this has been done without the approval of the FIA technical delegate, Tsunoda is required to start the race from the pit lane.
It means that all of the drivers who received back of grid penalties will move up one place from their provisional starting positions, including championship leader Verstappen.
The Red Bull driver was due to start 15th on Sunday, but will now move up to 14th place, serving as a small boost to his hopes of a fightback victory.
Verstappen topped qualifying by six tenths of a second on Saturday despite completing just one run in Q3, and has been tipped for a potential victory by many in the paddock. Mercedes driver George Russell thought Verstappen could win the race “comfortably” despite his low starting position.
Asked about his chances of winning from so far back after qualifying, Verstappen said: “I need a bit of luck for that.
“You need to have a bit of luck in the first few laps so you don't lose a lot of time in the opening laps. If there will be a DRS train, then it becomes much more difficult to overtake.”
Leclerc - who sits 80 points shy of Verstappen in the championship - will move up to 15th on the grid ahead of Esteban Ocon, Lando Norris, Zhou Guanyu and Mick Schumacher.
Valtteri Bottas also gains a position, rising from 14th to 13th as he does not have a back of grid penalty because of his separate power unit and gearbox changes.