The Brazil forward underwent tests at hospital on Monday and “is not at 100 percent” according to Tuchel, who said the results were otherwise reassuring.
The world’s most expensive player came off early in the second half of a 2-2 draw at Bordeaux on December 2 after hurting the same groin he injured playing for Brazil against Cameroon last month.
“He trained yesterday (Sunday) but not at full intensity. That’s why he’s not able to play” at Orleans, said Tuchel.
PSG’s last two league matches, at home to Montpellier and away to Dijon, were postponed amid ongoing protests across France and the threat of further terror attacks following last week’s shooting in Strasbourg.
“It was a bit difficult because Thursday they told us that the match against Dijon was off, but Friday they said it was possible we play on Sunday,” Tuchel said. “And then Friday night they said it wasn’t possible.”
The German also sowed further doubt over the future of midfielder Adrien Rabiot, who is out of contract at the end of the season.
“I cannot guarantee that ‘Adri’ will finish the season with us,” said Tuchel, adding that the France international “hasn’t said yes to PSG, that’s why everything is possible.”
The 23-year-old Rabiot, who refused to accept a berth on France’s standby list for the World Cup, has turned down several offers from the club to extend his deal at the Parc des Princes.