Khaman Maluach and his teammates on the Duke Blue Devils lost against the University of Houston on Saturday night in a semifinal of the NCAA men’s basketball tournament. Now, he may be facing a new opponent off the court: the U.S. government. The immigration status of Maluach, a star freshman center from South Sudan, appeared to be in question Sunday, one day after Secretary of State Marco Rubio revoked the visas of all South Sudanese passport holders living in the United States. He said the measure was effective immediately. In a social media post, Rubio said the move was “due to the failure of South Sudan’s transitional government to accept the return of its repatriated citizens in a timely manner.” Maluach, who grew up as a refugee in Uganda and played on South Sudan’s basketball team at the Paris Olympics, is widely seen as a first-round pick in this year’s NBA draft if he chooses to turn professional. He left after the game Saturday night without addressing the media, and he could not be immediately reached for comment Sunday. But Frank Tramble, a spokesperson for Duke, said in a statement that the university was aware of Rubio’s announcement. “We are looking into the situation and working expeditiously to understand any implications for Duke students,” he said. Last week, several schools including Harvard University, Ohio State, the University of Colorado and North Carolina State have made statements saying that the visas of some of their international students had been revoked. The moves come as the Trump administration continues its overall crackdown on immigration. Last month, Rubio said he revoked the visas of more than 300 students, visitors and others. This article originally appeared in The New York Times.