He said: “It’s the reality of end of the season and the end of March; the reality of having players in European matches and more than just one competition with all the cups going on.”
Tuchel picked an expanded 35-man squad for the Uruguay and Japan games at Wembley.
He split his players into two camps across the fixtures, the first made up primarily of fringe players and the second of more regular players.
“We have players in camp that have already played more minutes than last season, so there is some concern,” said Tuchel.
“The players needed and deserved the mental break from football. We could see the energy with which they came back into camp and to reconnect now in the new environment.
“We want them to perform in their clubs, but the reality is it’s our last camp before we leave to America, so we want to reconnect to our principles.
“It’s disappointing but I’m not upset with the players. I’m not angry.
“I got the feeling that everyone was desperate to come. Some of the injured players even stayed to do their treatment. That shows they want to be around the group.
“No-one left straight away. It’s a good spirit and that’s how it should be.”
The World Cup in the US, Canada and Mexico runs from 11 June to 19 July.
England will play friendlies against New Zealand and Costa Rica in June.
They open their World Cup campaign against Croatia on 17 June and face Ghana on 23 June and Panama on 27 June.