Mercedes say Lewis Hamilton’s health is “improving” – but still do not know whether he will be able to race in the year’s final grand prix this weekend.
Hamilton remains in isolation and must return a negative test result before he is allowed to travel to Abu Dhabi.
“His condition’s improving but we won’t know closer to the time if he will be driving,” said team boss Toto Wolff.
“We’ll do everything we can to get him in the car and we know he’s determined to be back as soon as possible. But his health is our main priority, so we will see what the situation is and then make the call.”
George Russell is in line to replace Hamilton if he cannot race.
The 22-year-old Williams driver starred on his Mercedes debut in Bahrain and was prevented from winning only by a pit-stop mix-up and then a puncture.
Russell has been named as Mercedes’ representative alongside Valtteri Bottas in the official FIA news conference on Thursday.
The latest Mercedes could put Hamilton in the car and still race is on Saturday for qualifying.
The team said it was “possible” they would make the decision as to whether Hamilton races as late as before Saturday’s final practice session, which runs for an hour and starts at 10:00 GMT, three hours before qualifying.
Hamilton released a video message on social media on Tuesday in which he said he was “feeling great” and had just completed his first physical training session since his positive test.
“It has been one of the hardest weeks I’ve had for some time,” he said, adding: “I hope I can get back in the car soon.”
The pit-lane tyre mix-up on Sunday, which affected both cars as they were stacked one behind the other, was caused by a radio issue which led to some mechanics not getting the message to take out tyres.
Wolff said it had “uncovered an underlying problem with our intercom, and we’ve put measures in place, both technically and in the way we operate, to make sure it doesn’t happen again”.
He also said Mercedes will be running a “slightly different livery” on their cars in Abu Dhabi “featuring everyone’s name on the car to honour the huge commitment and determination from everybody in (the team’s UK bases at) Brixworth and Brackley”.
“Everyone has pushed hard this year, raising the bar through this massively intense season, and we hope this gesture goes some way in showing the appreciation we have for everyone involved,” Wolff added.