"I don't really understand why our league started so early, but they did, so it's a really difficult situation for the clubs. Look at Tottenham, who had so many players [nine] in the semifinals of the World Cup. They had to put players straight into matches on the back of very little pre-season. It was an impossible situation for the coaches, really."
The Premier League had more players (39 out of 91) from semifinalists England, Belgium, Croatia and France than any other league and yet started on August 10, earlier than all of major leagues apart from France. La Liga started on August 17, Serie A on August 18 and the Bundesliga on August 24.
Despite his frustration, Southgate said he had not raised the issue with the Football Association or Premier League.
"I hadn't looked into when the season started until when we got back from the tournament," he said. "Maybe they [the Premier League] were expecting us to be back by the end of June. I assumed the rest of the world were going to be there until the middle of July.
"It's always easy to make a comment like that and not know the complex scenario the decision-makers had to go to, because that happens to me quite a lot.
"I think everybody knew when the final was going to be and the semifinal and that they would be away for a period of time.
"It's a bit like our clubs in the Champions League. Some of the rest of the leagues in Europe help them and adjust the fixture list and I'm sure our clubs would appreciate that because in the end, they're representing English football and we want them all to do well."
It was a theme endorsed by Croatian defender Dejan Lovren, who played in the World Cup final and also faced England in Saturday's Nations League goalless draw. Lovren was out of the Liverpool team at the start of this season, as he recovered from Russia, and only recently made his first league start.
He pointed to his Liverpool teammate Mohamed Salah, who has left the Egypt squad with a muscle injury, and Croatia colleague Luka Modric, as evidence that the top players are struggling to find their best form after the World Cup.
Asked if he thought Harry Kane, for example, looked jaded against Croatia, Lovren replied: "You can't say that on just one game. Maybe yes, maybe no. It's not only him. A lot of Croatian players are all exhausted emotionally.
"It's the same for England, trying to get over not going to the final. They felt these emotions about how the fans would react in England. It really wasn't easy. Then you have such a short period of rest. It's not so easy to adapt straight away.
"I definitely feel different to how I normally would, 100 per cent. It just isn't the same if you haven't started from day one in pre-season. I haven't even had a pre-season with my team.
"The most important thing is to get your form, but all the players [who went to the World Cup] are having this period of adaptation. Even Luka [Modric] said to me he is struggling."
