The Borussia Dortmund midfielder was not even on the bench for his side's 0-0 draw on Saturday but his coach has insisted it was not a form of "scolding"
The Japan international was substituted after 55 minutes of the 2-0 victory over Ingolstadt the previous weekend and did not even feature on the bench on Saturday.
Tuchel says Kagawa was not mentally ready to play against Hertha but he will hope for a recall when Dortmund take on Stuttgart in the DFB-Pokal on Tuesday.
"Obviously I talked with Shinji about not calling him up for Berlin," the coach said. "Those decisions are part of the game.
"Leaving Kagawa out wasn't a part of my general agenda. It doesn't always have to be seen as a scolding. I didn't have the feeling that Shinji's mind is free enough to play on his full potential on Saturday.
"We invested a lot on Saturday. We had a lot of intense runs and sprints, but we will field the best available team.
"We don't have to rotate yet because of the strain. We will field the team that is tactically best suited versus Stuttgart."
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A player Tuchel did not see eye-to-eye with was Kevin Grosskreutz, who could face his former club for the first time having moved to Stuttgart in January after half a season at Galatasaray, where he failed to make an appearance.
Grosskreutz was sold to the Turkish club in September following a public spat with Tuchel, who followed the lead of Germany coach Joachim Low in questioning the 27-year-old's professionalism.
"There was never doubt about Grosskreutz's potential," Tuchel said. "We disagreed over the ETA of his comeback [from injury] - he wasn't in good physical condition."
Last month, Low stated Grosskreutz was not in contention for a place in his Euro 2016 squad.
Speaking at a German Football League event, Low said: "I was in Istanbul and talked with the Galatasaray coach, who told me that Kevin flew home nearly every weekend from Friday to Sunday.
"You don't do that when you are part of a team. I have limited comprehension over how he has handled his career."