Lewis Hamilton has been forced to abandon his return to track action after he complained of feeling unwell.
Hamilton was scheduled to complete a full day of tyre testing in Abu Dhabi - the scene of his championship defeat by Nico Rosberg on Monday - but was replaced after only the morning session.
Pascal Wehrlein, the Mercedes junior driver who has raced for Manor this season, was drafted in to take over Hamilton's duties. Hamilton also withdrew from a tyre test in October with a sore foot.
"Lewis felt unwell so Pascal stepped in for the later runs," a Mercedes spokesperson said.
Hamilton, 31, was back at the Yas Marina Circuit only two days after his controversial tactics in the title-deciding race provoked Toto Wolff, the Mercedes boss, to threaten disciplinary action against his driver.
Mercedes were angry that Hamilton's move to back Nico Rosberg into the chasing pack - in a desperate bid to win him the championship - could cost the team victory. Hamilton also ignored two direct orders to pick up his pace.
Wolff, who appeared alongside Rosberg at a sponsors' event in Kuala Lumpur on Tuesday, insists he remains in "two minds" as to whether Hamilton will be punished.
Mercedes, who won all but two of the 21 grands prix this season and sealed the constructors' championship with three races to spare, strengthened their so-called 'Rules of Engagement' earlier this season after Hamilton and Rosberg crashed in Spain and then Austria.
"There is no rush or time pressure with anything," a Mercedes spokesperson said on Monday when asked about possible action being taken.
"Our focus right now is on celebrating the new champion".
Rosberg toasted his victory in the Amber Lounge nightclub in Abu Dhabi, where he was joined in his celebrations by some of F1's stars.
Hamilton, however, attended a different event on the same night, the F1 Abu Dhabi Grand Prix event at the VIP Room nightclub, where hip-hop star Drake performed.