The World Cup winner has been out since suffering an ankle injury in the Coupe de France final win over Saint-Etienne on July 24, with his participation in the latter stages of the Champions League subsequently put into doubt.
His recovery has been swift, though, and although he is not expected to start against La Dea, Tuchel hopes to finish the match with him on the pitch if needed.
"If he has a good training session today and nothing extraordinary happens, he will be with the team tomorrow,” the former Dortmund boss said in the pre-match press conference.
“We are very happy that he is with the group and that we can have the possibility of finishing the match with him.”
With Mbappe not fully fit and Marco Verratti and Angel Di Maria both out, the onus will be on Neymar to step up as PSG’s star player, and Tuchel believes the Brazilian is up to the task.
"I have the impression that there is always a lot of pressure on him, but he likes it," Tuchel said, speaking about Neymar.
"He is used to playing with this pressure.
"We are very happy that Kylian is also with the group and that we can have the possibility to finish the match with him, because the two like to play together.
“Neymar is decisive on the big matches and I am convinced that he can be the key man for us. He has the necessary quality for this kind of situation."