Button – in Fernando Alonso’s MCL32 for this weekend only as the Spaniard competes in the Indianapolis 500 – has received a 15-place grid penalty thanks to a new turbocharger and a new MGU-H element, both the car’s fifth of the season (exceeding the permitted four).
“It’s awful for Jenson and awful for McLaren,” said racing director Eric Boullier, “and not expected at all. But it’s Monaco, so we’ll try anything we can.”
Button’s misfortune means both McLarens now go into qualifying facing grid drops. Team mate Stoffel Vandoorne has already been penalised three places for causing a collision with William’s Felipe Massa in the last round in Spain.
With both drivers set to start Sunday’s Grand Prix at or near the back of the grid, McLaren are expected to focus the rest of their Saturday running on optimising race set-up.