England coach Gareth Southgate has said he is worried that only 54 players eligible for his team -- 24.5 percent -- started Premier League matches last weekend.
The number was the lowest since the Football Association began analysing lineups three years ago.
"This is just the missing piece that everybody is keen to resolve," Southgate said. "All of the big clubs, whenever I visit them, are wrestling with this issue.
"If a lot of those players had a couple of years of first-team experience, it would be a lot easier for their first-team manager to select them. But that is a conundrum we have got to solve."
England reached the World Cup semifinals for the first time in 28 years and qualified for the final four tournament of the inaugural UEFA Nations League, taking place in June.
"What's clear is that we can't allow the trend to continue as it is, because at what point do we stop?" Southgate said.
"Everybody saw the impact and the success of the national team in the summer and I think it is now prerogative that, while we still want a competitive Premier League that brings a lot of focus into our country as well, it's just trying to find this missing piece of development for English football."
After 14 Premier League matches this season, the average number of English starters is 29 percent, down from 33 percent across the last 38-game season.
"It is incredible," Southgate said. "Nobody can tell me that if players are good enough, they will come through. That is not true. There are plenty of players who are good enough.
"The quality of our academy system is very high. So I know that around the country lots of people in youth development are really keen to get together and find a solution to that 17-21 age bracket and how we get those players playing.
"Although we are in a position where we can lead some of those discussions, it is not a case that the clubs are not on the same page with that. They are very much looking at how to bridge that gap as well."
Southgate added that he believed more young players could follow the example of Jadon Sancho, who left Manchester City for Borussia Dortmund in order to play first-team football.
"For England, young people brave enough to travel, it's good for their development, for their maturity," he said. "That's definitely something that people have noted and it will happen more and more."
And Southgate warned that the volatile nature of managing in the Premier League could also cost young English players chances.
"When the position of so many managers is precarious, and there isn't long-term stability, I can understand why they are loath to risk," he added.