The University of Texas athletics department announced Thursday that 13 of its football players have either tested positive for COVID-19 or are "presumed" to be positive for the disease. The tally includes two positive cases discovered from initial surveillance testing conducted last week, according to a statement. All 13 players are self-isolating, and 10 more are in self-quarantine after contact tracing, the statement said. Texas also identified four football players who have tested positive for the COVID-19 antibody.

Big 12 teams were cleared to begin voluntary workouts at the beginning of this week. As college athletes around the country have returned to their campuses for workouts, numerous schools have announced that players have tested positive for the virus.

The rate of positive cases for the Texas football team is high compared to that of peer schools who have announced their test results. Baylor, for example, announced Tuesday that three of 59 tested student-athletes had the virus. Of those three, two were asymptomatic.

Texas did not reveal how many of its 13 players who tested positive are experiencing symptoms. But the school did say that the 10 who are in self-quarantine after contact tracing are not experiencing symptoms.

Elsewhere in the state, Texas Tech announced Monday that student-athletes from its football, men's track and field and women's basketball programs have tested positive for the virus. Texas A&M and Houston have also announced positive test results, and Houston went so far as to suspend workouts last week after six athletes with symptoms of COVID-19 tested positive for it last week.