The world's most expensive player has been out of action with the problem since the win over Montpellier on February 1 and could miss Saturday's game against Amiens. Despite his injury, the Brazilian reportedly took some time out of his recovery to attend a business trip in Germany.
"I've known for weeks. He organized it and was clear with the club. There's no problem," said Tuchel after being questioned by the country's press, which criticised the Brazilian forward's attitude.
He also had time to discuss advertising commitments with his player sponsors: "You can always decide if a player should rest. We discussed it. I know when a player can fly and we make that commitment. The communication between me and the club is very good".
However, it's not all bad news, as Tuchel insisted that Neymar would be fit for the clash at Signal Iduna Park.
"Whether or not he plays on Saturday (against Amiens), he will be in Dortmund, I'm sure of it, but without being in the best shape he was in two weeks ago," said the former Dortmund boss.
"But he will help us. I am sure and convinced of that."
Neymar missed last season's surprise Champions League last-16 defeat by Manchester United with a foot injury, and also sat out the second leg of the loss to Real Madrid at the same stage of the competition in 2018.
PSG have still not reached the Champions League semi-finals since their Qatari owners took over in 2011.