Wolves boss Nuno Espirito Santo has echoed the fears of Pep Guardiola that next month's international break could lead to a fresh coronavirus outbreak in the Premier League.
World Cup qualifiers are due to take place in South America, North and Central America, and Europe, while in Africa, the final group matches of the Cup of Nations qualifiers have been arranged.
Most remaining games in the second round of Asian qualifying for the 2022 Qatar World Cup are to be postponed to June because of Covid-19 disruption.
A number of Wolves players are due to link up with their countries including Rui Patricio, Nelson Semedo, Conor Coady, Pedro Neto, Ruben Neves, Romain Saiss and Adama Traore.
Just two new positives were found after 2,915 players and staff were tested in the Premier League's latest round of coronavirus testing but Nuno is worried about the risk extra international travelling poses.
"It's a big concern for everybody and for all the managers," he said. "All the squads in the Premier League have many players in the national teams, and with some national teams the current situation doesn't allow players to travel to that country.
"Everybody is worried but at the same time everybody is waiting for a decision so we can allow players to normally go to their teams and return safely to compete. It is the big issue.
"There is no manager at this moment who is not concerned about the welfare of their players."
Manchester City boss Guardiola, speaking earlier this week, said the only way to limit the spread of Covid-19 was to maintain strict limits on movement.
He said clubs had received no guidance regarding the window but that City would give advice to their own players before they travelled.