Eric Garcia will miss around five weeks of action after suffering a hamstring injury in Barcelona's 1-1 draw at Granada.
The 21-year-old center-back was replaced by Clement Lenglet after 54 minutes on Saturday, and tests carried out by Barca on Sunday confirmed the severity of the problem.
Garcia, who signed for Barca on a free transfer after his Manchester City contract expired at the end of 2020-21, has played 20 games so far this season, keeping four clean sheets.
Xavi's team have a number of players back following injury or positive COVID-19 tests, including Memphis Depay and Sergiño Dest, but will now be without Garcia until around the middle of February, while Gavi will also spend some time out after being sent off against Granada.
Barca host Real Madrid in the semi-final of the Supercopa de Espana on Wednesday, with Xavi having confirmed forward Ansu Fati will return from a hamstring injury that has kept him out since November.
The Spain international, who inherited the number 10 shirt worn by Lionel Messi, scored three times across five LaLiga appearances earlier this season following a 10-month absence with a serious knee injury.