Barcelona have confirmed that Lionel Messi has spent today undergoing tests "to assess the evolution of the kidney problems" that troubled him towards the end of last year.
The examinations, which will carry over into tomorrow, are expected to keep the 28-year-old out of Wednesday's Copa del Rey clash against Valencia.
However, in a short statement on the club's official website, Barca insisted that their talisman will return to training before the weekend's clash with Celta Vigo.
According to Spanish publication Sport, Messi may even undergo a minor procedure to remove kidney stones.
The report adds that the operation does not require the attacker to spend a prolonged period in hospital.