Manchester United have been warned that Odion Ighalo may not be ready to play for a month.
The Nigeria international has joined United on loan from Shanghai Shenhua for the remainder of the season as Ole Gunnar Solskjaer was desperate to sign a new striker in the January transfer window.
But Ighalo's last match came on December 6 when he played 23 minutes of Shanghai Shenhua's 3-0 victory over Shandong Luneng in the final of the China Cup.
United are next in action on February 17 as Solskjaer's side travel to Stamford Bridge to face Chelsea.
And according to Quique Sanchez Flores, who managed Ighalo at Watford and in China, the 30-year-old will not be fully fit for the clash against Frank Lampard's side.
'Mainly, the problem is how they train in China. It is not the same as in England,' Sanchez Flores said in an interview with The Athletic.
'Is he really ready for first-team matches in the Premier League because the physical difference is so big? He probably needs one month to recover the full rhythm.
'The good thing is he knows his body well, works hard on injury prevention and he is always working after training.
'I should say, also, that I felt in China, he gave exactly the same effort and quality as he gave me four years ago.
'We had the feeling in China that he could recover a high level with any team in Europe.'