- Tag results for Neymar
Neymar's father admitted that it is impossible to leave the world's most expensive player out of the rumour mill.
PSG signed Leandro Paredes but their offers for Idrissa Gueye and Thiago Mendes were turned down.
Tuchel's admission came after newspaper Le Parisien claimed on Sunday evening that Neymar had suffered a hairline fracture of the fifth metatarsal.
Mbaye Niang had equalised for Rennes in the first half, but Thomas Tuchel's side eventually ran away with the game after the break and are once again a massive 13 points ahead of Lille.
A fractured metatarsal curtailed the Brazilian's last season, and the recurrence comes just three weeks ahead of the first leg of PSG's crunch Champions League clash against Manchester United.
Guingamp, who have won just two league games all season, join Monaco, Strasbourg and Bordeaux in the semi-finals.
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.
Qatar-owned PSG are one of a number of clubs under scrutiny from UEFA's FFP regulations after splashing a combined total of more than 400 million euros in 2017.
Napoli beat Red Star Belgrade 3-1 on Wednesday, and Liverpool have to win by two goals at home to the Italians in a fortnight if they are to progress.
Everton's Richarlison, Neymar's replacement, headed in on the stroke of half-time for his third Brazil goal on his sixth appearance to secure victory for the Selecao.
Richarlison has won a place in the Brazil squad this season after impressing for Everton following his transfer from Watford.
Kylian Mbappe and Neymar scored late goals to give Paris Saint-Germain a 2-1 win over nearest challengers Lille on Friday as the French champions extended to 12 games their perfect start.
The 6-1 hammering of Red Star at the Parc des Princes on Wednesday was already the second time this term that all of Di Maria, Neymar, Edinson Cavani and Kylian Mbappe have scored in a game.
Messi, who had earlier twice hit the post, then got on the scoresheet in between goals from Harry Kane and Erik Lamela, before the Argentina superstar grabbed his second late on to seal victory.
Neymar "is perhaps not at 100%, but he's close," Tuchel said at a press conference ahead of Wednesday's Champions League home game against Red Star Belgrade.