Xavi's club confirmed on Monday that the 34-year-old is suffering with a back sprain.
While the injury is unlikely to worry national coach Vicente del Bosque as yet, it is nonetheless an unwelcome problem for Xavi, with Spain set to begin their World Cup defence on June 13 with a group game against the Netherlands.
"Xavi noticed a pain in his back after Saturday's game and tests this morning revealed a lumbar sprain, which will rule him out for about a week," a Barcelona statement read.
"The club's medical services have informed the RFEF (Spanish Football Federation) doctors of the situation in order to coordinate the recovery once the Spanish national team get together for the World Cup preparations."
Xavi played the last 13 minutes of Barca's final La Liga game on Saturday as they surrendered the title to Atletico Madrid at Camp Nou.
He has featured 47 times for the club in total this season, but has been forced to endure a rare campaign without silverware.
Provided there are no further injury problems or complications for Xavi, he is likely to make make his 15th World Cup appearance when Spain take on the Dutch in Salvador.
