Hamilton said he had not been feeling well on Thursday and Friday, when he was also up until midnight working with his engineers.
Australian Casey Stoner ran away with the delayed MotoGP season-opener from pole position on Monday to complete a hat-trick of wins at Qatar's Losail International Circuit. Racing in warm dry conditions after Sunday's start was postponed due to heavy rainfall at the desert track, the 23-year-old Ducati rider beat world champion Valentino Rossi into second place. Spaniard Jorge Lorenzo was third.
World champion Casey Stoner won the Qatar MotoGP Grand Prix in Doha on Sunday, the first race of the season and the first ever to be held at night under floodlights. The Australian, riding a Ducati, crossed the line first at the Losail International Circuit ahead of Spanish polesitter and debutant Jorge Lorenzo on a Yamaha, with Honda's Dani Pedrosa in third.
MotoGP world champion Marc Marquez took pole position at the Grand Prix of the Americas with seconds to spare on Saturday after clambering over a wall and sprinting down pitlane to jump on his spare Honda.
MotoGP great Valentino Rossi rolled back the years to win the Qatar season-opener for Yamaha on Sunday with Italian riders sweeping the podium places after a thrilling duel under the Losail floodlights in Doha.
Italian MotoGP great Valentino Rossi plans to keep on racing until he is nearly 40 after signing a new contract for the 2017 and 2018 seasons with Yamaha that should see out his career at the Japanese manufacturer.