Major League Soccer announced Sunday that 18 players and six staff members tested positive for COVID-19.

The number of positives came after the league started testing since teams began full team training on June 4. A total of 668 players from 25 teams have been tested since that time. Only one of the league’s teams was not able to commence training fully.

A few teams have already arrived to Orlando, Fla., prior to the MLS is Back Tournament that starts July 8. Two players from a group of 329 people tested positive, and those players had just arrived on site.

The league’s protocol for any positive polymerase chain reaction, or PCR, test is for that person to receive a “clinical assessment by a health care provider,” then moved to an isolation area in the hotel until that person is medically cleared.

Two PCR tests were administered 24 hours apart about three days prior to teams starting training. After that, players and staff took a PCR test every other day.

Players, staff, league officials and referees took an additional two PCR tests, 24 hours apart, about three days before heading to Orlando. After arriving there, they took one more test and quarantined while waiting for the result.