Former Barcelona frontman Neymar has been absent with a rib injury since the 5-0 win over Montpellier on February 1, and without him PSG have claimed league wins over Nantes and Lyon and a Coupe de France victory at Dijon.
"For Neymar, we have to decide with the doctor after the test," head coach Tuchel said.
"Whether he plays tomorrow or not, he will be in Dortmund for sure, but maybe not at his best like he was two weeks ago.
"But I am convinced he will help us and with this game we will keep going, and we hope he will be uninjured and be able to play a few games in a row until the end of the season."
Tuchel explained he wanted Neymar to play in every game.
"Yes, but I cannot push him," Tuchel said. "I have the advice of the medical staff but we decide together.
"I want him to play all the time. There are a lot of things to think about. There is the opinion of the medical staff, the player, the feeling that the player is not worried about playing.
"We need to talk to one another and think about it, but in the end we have to make very clear decisions. No risks against Lyon and no risks against Dijon. In the end he agrees and I think it is a good thing because we will make the common decision together."
Tuchel stressed he had no complaints over Neymar's trip to Germany on Thursday to promote a clothing range.
"I knew about it for a few weeks," said Tuchel. "It was organised with the club. It was clear for almost six weeks. It's not a problem."
Former Dortmund boss Tuchel said Marquinhos, Marco Verratti and Idrissa Gueye would be fit to return to the first team at Amiens, barring any setbacks in training on Friday afternoon, after missing the Dijon cup game through injury.