Odion Ighalo has not been working at Manchester United's training base since joining the club due to concerns over the coronavirus.
The PA news agency understands United have taken extra precautions with their new signing after it was decided the striker would not join up with the squad at a training camp in Spain.
United were concerned about border restrictions after Nigeria international Ighalo, who signed for United on loan from Shanghai on deadline day, arrived from China.
The club feared Ighalo might not have been allowed back into the UK had he travelled to Spain due to a tightening of regulations regarding people who had been in China within the previous 14 days.
It has now emerged that United have even gone even further than current governmental guidelines suggest and asked Ighalo not to train at their AON Complex at Carrington during this 14-day incubation period.
The 30-year-old former Watford player has instead been working on his fitness at a city centre location close to where he is staying, using a personalised fitness programme from the club.
United recognise the chances of Ighalo having been exposed to the coronavirus are statistically minute, but have taken the decision after considering all aspects of their business.
Manager Ole Gunnar Solskjaer decided to take his squad to Marbella for warm-weather training during United's winter break.
They are next in action when they travel to Chelsea on Monday.
Ighalo has not played a competitive match since December 6 but Solskjaer has indicated he will be in contention to make his debut.
"He is going to travel with us," said Solskjaer earlier in the week. "We will just see his fitness work this week and I think we will get him sharp.
"We want to integrate him as quickly as we can because, of course, he is desperate to play for us."