Clemson’s football team has 23 confirmed cases of COVID-19 since its return to campus two weeks ago, according to a source, after the school announced 28 new positive tests among student-athletes and staff on Friday.

The school performed a total of 315 tests in the past week, with 28 people testing positive, the bulk of which were football players. According to a source at the school, 21 players tested positive, as did two members of the football staff, which is not limited to coaches. Last week, two other football players, as well as a men’s basketball player, tested positive during the school’s initial run of 169 tests.

While the state of South Carolina reported its highest number of total positive tests and highest percentage of positive tests to date on Friday, the rate of positive tests at Clemson in the past week is nearly double the national average.