Barcelona says striker David Villa has returned to hospital to treat his case of kidney stones.
The Spanish club said on Thursday that "persistent pain" forced Villa to seek further treatment.
Villa spent Monday night in hospital and was released the following day.
The 31-year-old Spain international is doubtful for Barcelona's match at Granada on Saturday.
Villa missed several games this year due to a muscle injury, and has yet to recover his starting role since returning from a long layoff because of a broken leg last summer.