The England defender has not feature since Chelsea’s Champions League final win over,
Manchester City on 29 May – with Marcos Alonso replace him so far this term.
The 24-year-old was in England’s Euro 2020 squad but did not play once.
“He just needs to be patient. He’s in the race now and with a good mental attitude,” said Tuchel.
“It’s been difficult for him, from a Champions League win.
Then it was a tough Euros because he felt he could have played a part for England,
Ben keeps training for four or five weeks, then he had a personal break which is difficult.
“When I arrived I felt he was mentally tired which is unlucky because Marcos Alonso had a full pre-season.
We had some talks with him and no further worries with him.”
Spaniard Alonso has played all five of Chelsea’s games at left wing-back,
in their unbeaten start to the Premier League season and Uefa Super Cup win.
The Blues start their Champions League title defence on Tuesday at home to Zenit St Petersburg (20:00 BST).