Kylian Mbappe has been admitted to the hospital with acute gastroenteritis, the club has announced, following his absence in Real Madrid’s opener in the FIFA Club World Cup. Real Madrid suffered without him in Xabi Alonso’s first match in charge, drawing 1-1 with Saudi Arabian side Al-Hilal.

“Our player Kylian Mbappé is suffering from an acute case of gastroenteritis and has been admitted to hospital in order to undergo a series of tests and follow the appropriate course of treatment,” Real Madrid said in a statement.

There’s no timetable for Mbappe’s return, but the recovery from gastroenteritis can take over a week which would put Mbappe at risk of missing Real Madrid’s group stage match with Pachuca on Sunday. After scoring 31 goals in his debut season for Los Blancos, the stage is set for Mbappe to impress this season, but there has been much change at the club under Alonso and with the arrival of Trent Alexander-Arnold. Gonzalo Garcia started the match against Al-Hilal in Mbappe’s absence, scoring Real Madrid’s lone goal.

With Mbappe sidelined, it will take longer than expected for Alonso to get the full Real Madrid squad together and Garcia could continue to start after scoring 26 goals in all competitions last season. Next up for Real Madrid will be Pachuca on Sunday before clashing with RB Salzburg on June 26. RB Salzburg is currently leading Group H after their victory over Pachuca to open the tournament which could make things interesting during the remainder of the group stage.