• “At the moment it’s not sustainable,” said Moeen, who retired from Test cricket last year.
• The 50-over One-Day Cup is currently being contested by counties missing several players involved in The Hundred.
England all-rounder Moeen Ali expects more players to retire from some formats because of the packed schedule.
Test captain Ben Stokes quit one-day internationals in July, while he and England team-mate Jonny Bairstow have opted to miss The Hundred.
“At the moment it’s not sustainable,” said Moeen, who retired from Test cricket last year.
Moeen, 35, is concerned that 50-over cricket could vanish amid the increasing dominance of Twenty20.
Speaking after his Birmingham Phoenix side lost to Trent Rockets in The Hundred on Saturday, he said: “Something has to be done because I fear losing the 50-over format in a couple of years because it’s almost like the long, boring one. There’s no importance given to it at the moment.
“International cricket in all three formats is by far the best cricket to play, but I do worry there are so many tournaments out there that players are retiring more now - and you’ll see more retiring soon - because of overlapping schedules.”
The calendar has become more congested in recent years because of an increase in global events and the emergence of more T20 franchise competitions around the world plus The Hundred in England and Wales.
The 50-over One-Day Cup is currently being contested by counties missing several players involved in The Hundred.
India bowler Ravichandran Ashwin recently questioned the long-term survival of the 50-over game and said he no longer watches 50-over games on television.
Announcing his ODI retirement, 31-year-old Stokes said: “There is too much cricket rammed in for people to play all three formats now.”
Interim England and Wales Cricket Board chief executive Clare Connor told BBC Sport this week that Stokes’ message had “absolutely” been heard.
“It’s something that we have got to grapple with - that’s us with players, other boards, the International Cricket Council and the Professional Cricketers’ Association,” she said.