Jenson Button and Fernando Alonso are expected to start the Mexican Grand Prix from the back row of the grid after making engine and gearbox changes ahead of the race weekend.
Alonso has taken his 11th new engine of the season this weekend, resulting in a 10-place drop plus a further 5-places a new gearbox. He ran the latest specification of the Honda engine in Austin, but dropped from fifth place to 11th with a fuel injector issue towards the end of the race.
Button will use the latest Honda power unit for the first time in Mexico, but fit one just for Friday morning practice and a second for the rest of the weekend. The two planned changes will take his engine count for the year to 11 and is expected to result in a 50-place grid penalty. However, the two new power units can then be used without penalty at the final two rounds in Brazil and Abu Dhabi where the team is expecting to be more competitive.
McLaren has made no secret that it is expecting to struggle this weekend due to the circuit's long straights and the extra demands the high altitude puts on the turbo and energy harvesting of the MGU-H.