Lewis Hamilton will be without trusted race engineer Peter Bonnington this weekend as he bids to close out a sixth world championship.

Bonnington is undergoing a medical procedure at home in England and is absent from Sunday’s round in Mexico and the following race in Austin next weekend.

Bonnington talks to Hamilton on the radio during the races and has worked alongside the Briton at Mercedes since 2013, aiding four of his five world titles.

Sunday’s race will be the first time in 136 rounds that Hamilton will start a grand prix without Bonnington in his ear.

Bonnington will be replaced by Marcus Dudley, Hamilton’s performance engineer, with Dom Riefstahl stepping up to fill his shoes. Mercedes expect Bonnington to return for the penultimate round in Brazil.

Hamilton will move to within one championship of Michael Schumacher’s record if he outscores team-mate Valtteri Bottas by 14 points in Mexico City on Sunday.