Jurgen Klopp has questioned the scheduling of international matches after Liverpool midfielder Adam Lallana suffered an injury on England duty.
Lallana could be out on the sidelines for up to a month with a thigh injury he picked up during England's World Cup qualifier against Lithuania on Sunday.
The 28-year-old played the entire 90 minutes in the 2-0 victory at Wembley, having featured for over an hour in a friendly defeat to Germany just four days earlier.
Klopp has said it was wrong for England to play a quality opponent so shortly after Liverpool's intense draw with Manchester City prior to the international break.
"It's hard for us to lose a player like Adam for four weeks, which could be eight games -- it's a lot," Klopp told Sky Sports.
"Whoever thought it was a good idea to play Manchester City and Liverpool on a Sunday night and then Germany against England on the Wednesday, it makes no sense.
"We all have to start to work much better together: the FA, Premier League, television and the clubs because we're trying to sell the best product.
"City and Liverpool was one of the most intense games in the league. So you can't have the highlight games like that then Germany against England and this and that.
"We all do this on the back of the players and a lot of players got injured on this international break.
"Friendly games at this stage of the season? Someone wants to tell me that it's important because we'll learn something about the players.
"Eight weeks from now we have more friendly games for the national team. Players should have a holiday but they're playing friendly games for their national teams."
Sources have told ESPN FC that Klopp has spoken to Gareth Southgate, which the England boss commonly does with club managers, following Lallana's diagnosis.
The Liverpool manager, ultimately, does not hold Southgate responsible for the injury suffered to a crucial player within the team.
"I don't blame anybody for this, especially not Gareth Southgate," he added. "I like him, we've had a few meetings. As a manager, I respect it's absolutely his decision to pick him.
"The media put him under huge pressure to pick the best lineup. If he had left Lallana out against Germany -- the press would have asked 'do you want to win?'"