It is claimed that talks between PSG and interested parties Barcelona and Real Madrid have continued this week, but there has been no breakthrough over a possible deal for the Brazil star.
Neymar has not played for the Ligue 1 champions since the 2-1 win at Angers in May, having sat out their pre-season matches and all three competitive games in 2019-20 due to an ankle injury that saw him miss the Copa America.
The forward trained with the first team this week and appeared to be in good spirits with his team-mates, leading to suggestions he could yet decide to stay at Parc des Princes.
Tuchel says the former Barca player could feature as soon as Sunday, when PSG face Toulouse, but only if his future has become clearer.
"Neymar is in good shape," he told a news conference. "He has had a good week with his team-mates. However, the club's position is clear: while his situation is unclear, he cannot play.
"If Neymar's situation became clear tomorrow, then he could play.
"The situation with Neymar is unsettling. It helps nobody. Everyone is used to this sort of situation around Neymar. The same thing happened when he was injured. It is normal with the biggest stars."
Midfielder Marco Verratti equally hopes his team-mate stays in the French capital beyond the transfer deadline of September 2.
"Neymar and I are close. However, I don't like speaking with him about his future," he said. "Obviously, I want him to stay. I would like it to be September 2 tomorrow."