Barcelona midfielder Xavi is expected to miss Saturday's Primera Division meeting with Granada after suffering a leg injury.
The 33-year-old was left out of the Spain squad that travelled to South Africa for Tuesday night's friendly, with a view to resting ahead of Saturday's match at Camp Nou, but medical tests have now discovered a muscle strain to his left hamstring.
A statement published on Barca's official website confirmed Xavi's condition would be continuously monitored and that his availability for the Granada game would be assessed through the week.
Cesc Fabregas was also unable to travel to South Africa due to an injured right knee but the former Arsenal midfielder returned to training on Tuesday.
Argentinian striker Lionel Messi, who has scored 14 goals this season, will miss up to eight weeks of football with a hamstring problem.