Liverpool boss Jurgen Klopp welcomed the collapse of the European Super League (ESL) but warned the reformed Champions League format will put further pressure on the fixture schedule.
The controversial ESL is "on standby" after nine of the 12 founding teams withdrew earlier this week.
But a revamped 36-team Champions League was agreed on Monday.
"You can't just introduce always more competitions," Klopp said.
"It's very good that the new Super League is off the table, but the new Champions League isn't great."
The new Champions League format is due to start in 2024 and run until at least 2033.
The number of clubs competing in it will increase from 32 to 36 with a revamped group stage that will see all teams play at least 10 fixtures.
"Ten games rather than six and no idea where to put them in," said Klopp. "The only people who never get asked are the coaches, the players and the supporters.
"Uefa didn't ask us, the Super League didn't ask us. It's just always 'play more games'. The new Champions League, what's the reason for that? Money ... I have no idea how we're supposed to deal with even more games.
"You can't have 20 teams in a league, two cup competitions, 10 international games before Christmas - these things aren't possible."
'Maybe we need 400 days in a year'
On Thursday night, Manchester City midfielder Ilkay Gundogan raised concerns over plans to change the Champions League by adding more matches, saying it was just the "lesser of two evils" compared to the ESL.
City boss Pep Guardiola is concerned that adding even more fixtures will increase the risk of injury to players.
"Of course there will be more injuries," he said. "These guys will finish an incredibly tough season, have five or six days off and then go to their national teams.
"We have to ask Uefa and Fifa to extend the year, maybe have 400 days a year. Maybe then they can find a solution on that."