For the second week running Neymar was missing in action as the Parisians slumped to a 2-1 defeat to Rennes in the French Ligue 1 on Sunday.
Despite Edinson Cavani giving the champions a first half lead, PSG could not hold on as they lost for the fifth time in six away fixtures stretching back to last season.
Neymar has been linked with a move back to Spain to join either former side Barcelona or Real Madrid with PSG reportedly rejecting bids from the two Spanish giants last week.
Tuchel rued the lack of creativity in PSG’s attack following Sunday’s defeat and has signaled his intention of keeping Neymar at the club.
"He will not leave without recruitment, it is not possible," Tuchel said at his post-match news conference. "It's clear - if he stays, we will have a player who will help us win.
"We lacked capacity for acceleration. There were small situations where space opened but we were not decisive."
Tuchel told Canal +: "I always say the same thing, the transfer window is open even more than 10 days and you think it will be settled tomorrow or the day after tomorrow?
"What I think is not important. Today my player cannot play because he has not done any training like the others. This is the situation, and nothing has changed."
Juventus forward Paulo Dybala is reportedly a target for PSG if Neymar secures a move back to Spain.
