Barcelona striker Neymar is believed to be suffering from anaemia, according to the Daily Mail.
Barca's medical staff found irregularities in the player's blood count when he underwent routine tests.
The club are said to not be too concerned with the discovery, but he is now on a refined eating plan and will be monitored closely over the coming weeks.
The 21-year-old, who became a marquee signing after his £50 million move from Santos this summer, is believed to have developed the condition as a result of his tonsillectomy.
Anaemia can cause extreme tiredness to sufferers, but the Catalans aren't said to be overly worried about the news.
According to the club's sporting director, Andoni Zubizarreta, the condition will not affect the young striker's chances of finding his feet at the Nou Camp.
He said: "We would have liked him to have been in perfect condition, but not many players arrive perfect for the pre-season.
"We'll help make sure he's in the right condition. It's not a concern."
Neymar is currently with the Barcelona squad as they continue their pre-season tour of the Middle East.
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