Fixture fatigue: What happens to players when the games pile up

“… It was early August when Liverpool manager Jurgen Klopp revealed his concern over the potential impact this winter’s World Cup could have on international players. Fixture congestion is nothing new (nor are managers’ complaints about it) but adding a major tournament into the mix mid-season, with only brief pauses before and after it, certainly is. ‘… Clubs competing in Europe have no free midweek until the turn of the year, so this round of fixtures will likely be added to the list for early 2023, further complicating life for teams who progress in cup competitions domestically and in Europe. …”
The Athletic