Liverpool boss Jurgen Klopp says players need to be looked after in a “better way” or it will “kill the game” with the Champions League final scheduled five days before England’s Nations League semi-final.
Liverpool face Tottenham on 1 June in Madrid and England play the Netherlands in Guimaraes, Portugal on 6 June.
About 10 players might be delayed in joining Gareth Southgate’s England squad.
“It’s not good planning,” said Klopp.
“Everybody looked at me when I said it was not such a good idea, and whoops, there are two teams in the Champions League final who are English, and if it had been a Dutch team it would have been the same.
“If we don’t learn to deal with our players in a better way, competition-wise, then it’s the only chance to kill this wonderful game. Because without the players, it’s not a good one.”
The German added: “But other people have to deal with that. It’s not Gareth’s fault, but planning something like this and being surprised at two top teams being in the Champions League final and a lot of players of these teams involved in the Nations League, that’s interesting planning.
“If we would plan something like this, we would be surprised every weekend that there is another Premier League game.”
The winners of the match between England and the Netherlands will face either Portugal or Switzerland in the Nations League final on 9 June.
Potential England squad members include Liverpool’s Trent Alexander-Arnold, Joe Gomez, Jordan Henderson and Alex Oxlade-Chamberlain.
Danny Rose, Kieran Trippier, Eric Dier, Dele Alli, Harry Winks and England skipper Harry Kane are Spurs players who could feature.
England internationals Ross Barkley and Ruben Loftus-Cheek are also likely to be in action for Chelsea on 29 May in the Europa League final against Arsenal in Baku.
Players like Alli have had just under a month off in the past year. He played in England’s first World Cup warm-up game on 2 June 2018 and the third-placed play-off match on 14 July. His first match of the season for Spurs was on 11 August.
England and Spurs captain Kane has not played since 9 April when he suffered an ankle injury, but is “hopeful” of being fit to face Liverpool in Madrid.
Southgate says his preparations have been made “a little bit more complicated” thanks to the all-English Champions League final.
“This is a challenge we have to deal with as a group of staff,” he said.
Last month Southgate suggested England’s attempts to win the inaugural edition of the Nations League would be a “mess” if one or more English clubs reached the final at Atletico Madrid’s Wanda Metropolitano.
On Thursday, he added: “For our young English players it is great that they are playing in matches that really matter while under pressure and they are being really successful, because that will help England in the long run.
“Although it makes our preparation a bit more complicated, that is a challenge we have to deal with as a group of staff. We have got to adapt. We are always telling our players to adapt so we have got to do the same.”