Ajax Amsterdam arrived with a skeleton squad of 17 in Denmark on Monday for a Champions League match against Midtjylland with 11 players testing positive for the coronavirus.
The Dutch club is without their two main goalkeepers and preparing to give 20-year Kjell Scherpen his debut in the competition on Tuesday.
Scherpen, who is 2.02 metres, is the only goalie in the reduced Ajax squad.
Ajax coach Erik ten Hag says of his selection issues: "It's not ideal but you have to deal with it. Every team can get the coronavirus. Now we have it."
Goalkeepers Andre Onana and Maarten Stekelenburg stayed home on Monday among a group of players including playmaker and captain Dusan Tadic.
Under coronavirus-related rules by the governing body UEFA teams must play in UEFA events if they have 13 players, including one goalkeeper, available.
In England, the Premier League said on Monday four had returned positive results in their latest round of COVID-19 tests conducted on players and staff last week.
The league said the individuals who had tested positive for the coronavirus would now self-isolate for 10 days.
"The Premier League can today confirm that between Monday, October 26 and Sunday, November 1, 1,446 players and club staff were tested for COVID-19," the league said in a statement. "Of these, there were four new positive tests."
A total of 48 people have tested positive for the virus in nine rounds of testing since the new league campaign began in September.
The UK government has allowed Premier League football and other elite sports to continue without spectators during the four-week lockdown from Thursday.
In the US, Baltimore Ravens All-Pro cornerback Marlon Humphrey says he has the coronavirus as several other NFL teams reported positive tests Monday, providing new concerns for a league trying to complete the season amid a pandemic.
The Green Bay Packers reported a player tested positive for COVID-19, and Arizona coach Kliff Kingsbury confirmed two Cardinals tested positive over the weekend.
In addition, the Browns conducted meetings remotely Monday after a player reported he is experiencing "COVID-19-related" symptoms.
It was a difficult day for the league as it nears the halfway point of a season that's already had its schedule altered by outbreaks of COVID-19.
Ravens coach John Harbaugh ruled Humphrey out for Sunday's game in Indianapolis, and said the team has stepped up efforts to monitor the players and keep them healthy.
The NFL administers daily testing, including game day and during bye weeks. Results of the tests generally come in overnight. Tests taken the day before the game determine if the player can play on game day.
On game day, they have their temperatures taken by contactless thermometers, are screened for loss of smell or taste and have other symptoms checked prior to entering the stadium.
The Green Bay Packers said one of their players had tested positive. According to multiple reports, that player is running back AJ Dillon.
In Arizona, Cardinals linebacker Devon Kennard says he has tested positive for COVID-19, but the franchise did not release the name of the other player who tested positive over the weekend.