COLUMBUS — Columbus Crew SC Wednesday announced it had four positive COVID-19 cases involving players following testing this week.

No additional positive results for players or staff were received following additional rounds of testing Wednesday.

The Major League Soccer club did not reveal which players tested positive.

All MLS players undergo Polymerase Chain Reaction (PCR) tests every other day, including the day before each match. The confirmation of a COVID-19 case occurs when a player receives two consecutive positive test results.

Upon receipt of initial positive results of two players Sunday, both were self-isolated under a strict and detailed protocol and extensive contact tracing and facility sanitization took place, the club said.

Columbus defeated the Red Bulls in its first-round game Saturday, 3-2.

After a scheduled off day Monday, two additional players had results that returned positive following Tuesday’s testing and self-isolated. Crew SC will continue to test each remaining day this week. It is scheduled to train Friday and Saturday ahead of Sunday’s Eastern Conference semifinal vs. Nashville SC at home.

“The health and safety of all players and staff remains the highest priority for the club,” a team statement said.

The four players will remain in isolation and will be monitored by the club’s medical staff.