Barcelona and Spain midfielder Xavi Hernandez suffered a slight back injury as his side missed out on the La Liga title with a 1-1 draw at home to Atletico Madrid on Saturday.
The 34-year-old, who has been included by Vicente del Bosque in his preliminary 30-man squad for the World Cup next month, is expected to be sidelined for a week and should be fit to join Spain's pre-tournament training camp early next week.
"The player noted the pain in the left side of his back after the game on Saturday," Barcelona said in a statement on their website on Monday.
"The tests carried out have confirmed a sprained vertebrae. The approximated time out is one week.
"The FC Barcelona medical staff have informed the medical staff of the Spanish Football Federation to coordinate in the player's recovery once the Spanish national team's training camp begins."