Soccer superstar Kylian Mbappe has been hospitalized with acute gastroenteritis, his club team Real Madrid said Thursday, June 19. “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,” the Spanish soccer team said in a news release. Mbappe, 26, had missed Real Madrid’s opening game in the Club World Cup tournament in Miami on Wednesday, June 18, according to the Associated Press. The team said Mbappe sat out of the contest because of a fever, the AP reported. After Wednesday’s game, Real Madrid head coach Xabi Alonso told reporters he hoped Mbappe would be available for the team’s next game on Sunday, June 22. However, it’s unclear if Thursday’s announcement that the 2018 World Cup winner has now been hospitalized changes the timeline for his return. Real Madrid is in the U.S. for the next month as the Club World Cup continues across the country, with its final being played on July 13. Real Madrid were among the favorites to win the first-of-its-kind tournament, which is a precursor to next year’s FIFA World Cup. As one of the most popular athletes in the world with more than 138 million followers across Instagram and X, Mbappe’s absence from the tournament is a major blow to its appeal, according to the AP. In the past, Mbappe has pushed through several injuries in order to return to the pitch during major tournaments. Last year, the French soccer star played through a broken nose during the European Championship tournament, opting to wear a face mask in order to rejoin his team. Gastroenteritis, commonly called the stomach flu despite not being influenza, is an intestinal infection that can cause a person to have “watery diarrhea, stomach cramps, nausea or vomiting, and sometimes fever,” according to the Mayo Clinic. Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer​​, from celebrity news to compelling human interest stories. “Symptoms usually last just a day or two, but occasionally they may last up to 14 days,” the clinic says, adding that the most common issue that comes from the illness is dehydration. “Hospitalization might be needed so that lost fluids can be replaced through an IV in their arms,” according to the Mayo Clinic. Mbappe has publicly spoken about his recent health issue.