FC Dallas have withdrawn from the MLS is Back Tournament starting this week after 10 players and one staff member tested positive for the coronavirus since joining the league's setup ahead of the competition.
Three other players from two other clubs have also tested positive, out of a total of 557 players currently in Orlando, Florida.
MLS is keen to become the first major men’s sports league to return in the United States, following the resumption of the NWSL in June.
A statement from MLS read: “Major League Soccer announced today that FC Dallas have been withdrawn from the MLS is Back Tournament due to 10 players and one member of the technical staff confirmed positive for Covid-19.
“Each of these positive tests either occurred upon the club’s arrival or within a few days of arrival.
“The decision was made in the best interest of the health of all players and staff participating in the tournament, and in line with protocols created in conjunction with local and national health authorities and infectious disease experts.”
MLS Commissioner Don Garber added: “The health of everyone involved in our return to play has always been our top priority, and we will continue to make decisions consistent with that priority.”
While there is clearly concern and disappointment from FC Dallas, club president Dan Hunt accepted there was little other option but to withdraw.
“We absolutely agree with the league’s decision to withdraw FC Dallas from the MLS is Back Tournament out of safety concerns for our players and staff,” Hunt said.
“We’re looking forward to resuming the 2020 season once the entire club is healthy and in position to play competitive matches at the highest level.”
MLS has not yet announced how FC Dallas' withdrawal will impact the tournament format, with the club originally scheduled to feature in Group B alongside the San Jose Earthquakes, Seattle Sounders and Vancouver Whitecaps.
The decision could also impact how the tournament will impact the league's eventual return to regular season play, with group stage matches set to count towards the 2020 standings.
Following FC Dallas' withdrawal, and with several other clubs yet to arrive in Orlando just days before the tournament is set to begin, Garber says that the league will continue to monitor the situation and make a more drastic decision should it become necessary.
“If there is a situation at any time that I believe that the protocols aren’t working, and the health and safety of our players is at risk, then I will make the decision to shut down the tournament," Garber told the Associated Press.
In a further blow to the tournament, reigning MLS top scorer and MVP Carlos Vela will not take part.
Vela will reportedly remain at home with his pregnant wife, Saioa, and their three-year-old son, Romeo.
MLS gave players the option to skip the tournament for health or family reasons, with Vela the most high-profile player to do so.
More than 132,000 people are reported to have died during the coronavirus pandemic in the U.S. so far, as concerns continue to mount over the country's handling of the crisis.