"We already expanded the squad this season because we make the reason clear," he said at a press conference.
"We had a World Cup in the middle of the season, we had a longer season, we had to play a longer season as well, with FA Cup. A shorter break.
"Every time the schedule is expanding, the load on the players is too much, it's such a great overload. Many colleagues of mine have pointed to that and I have pointed to that as well. But it keeps going. We keep expanding the schedule. Anywhere, it won't stop. Players can't deal anymore with this overload and I think that's what you say in this squad at the moment."