Denmark could field a weakened team against Wales in their Nations League game on 9 September, as a result of an ongoing row between players and the Danish Football Association (DBU).
Senior players have refused to sign a new national team agreement in a dispute over commercial rights.
Denmark's squad have until the evening of Sunday, 2 September to sign.
Denmark risk being barred by Uefa if they fail to fulfil the fixture, so could field players from lower leagues.
The Denmark women's team boycotted a World Cup qualifier against Sweden in October 2017 in a dispute over employment conditions.
Uefa ruled out ejecting the team from qualification, instead awarding Sweden a 3-0 win and fining the DBU £18,000.
But the DBU was warned that Denmark would be ruled out of any Uefa tournament if they cancelled another match in the next four years.
The DBU might therefore have no choice but to select a side drawn from the Danish Super League and First Division, for a friendly against Slovakia on 5 September and then the Nations League game against Wales on 9 September in Aarhus.
That could see Wales face a Denmark side missing Premier League stars such as Leicester City goalkeeper Kasper Schmeichel, Chelsea defender Andreas Christensen and Tottenham midfielder Christian Eriksen.
Eriksen - capped 82 times by Denmark - is a spokesperson for the Danish Football Players' Union (Spillerforeningen) and in a statement said he hopes the dispute can be solved.
"It is crucial, among other things, to control the agreements on the use of national team players for marketing," he said.
"Just that point has given us players a lot of problems in the last eight months, so we should like it solved.
"From the players' side, we are fairly well aware of what it takes to solve all the conflicts and move on.
"Our negotiation team is ready to talk to the DBU at any time, so we can reach a goal before the friendly match against Slovakia."
Before the Denmark game, Wales begin their Nations League campaign on 6 September against the Republic of Ireland at Cardiff City Stadium.