The Dallas Mavericks practice facility closed Sunday morning after forward Maxi Kleber tested positive for COVID-19, according to ESPN.
It was the second positive test since Friday for the Mavericks.
Starters Dorian Finney-Smith and Josh Richardson, along with key reserve Jalen Brunson, all are sidelined because of health and safety protocols after one of them tested positive.
It is unknown which player returned a positive test. All three remain quarantined in Denver, where the Mavericks were when the test results came in, The Athletic reported Sunday.
The Mavericks are conducting contact tracing to determine whether any other players or coaches will need to enter the minimum seven-day quarantine period.
Kleber, 28, was in the starting lineup on Saturday night when the Mavericks beat the Orlando Magic 112-98. He scored five points and added three rebounds and two blocked shots in 24 minutes.