The France international wasted a good chance in Wednesday's 3-1 win over Manchester United as his scoreless streak in the Champions League stretched to a ninth game.
⚽🎙 Press Conference with Thomas Tuchel ahead of Montpellier - Paris saint-Germain 🔴🔵https://t.co/iYPN2A7jpY— Paris Saint-Germain (@PSG_English) December 4, 2020
He is also without a goal in his past three appearances for PSG, failing to score from any of his nine shots in those games and finding the target only twice.
PSG face a huge clash with Istanbul Basaksehir next Tuesday, knowing that they are guaranteed a place in the last 16 should they avoid defeat.
And with that contest in mind, Tuchel will consider leaving out Mbappe for this weekend's Ligue 1 meeting against Montpellier.
"We will have to decide on that today," Tuchel said at Friday's pre-match news conference. "In my head there are several different possibilities.
"We have to make decisions for Tuesday as well. We may have some changes to make. But for Kylian personally, I am calm.
"For me he had a good game [against United], a better game than in matches he has scored in. He put in a lot of effort both in an attacking and defensive sense.
"He had a bit of bad luck with his chance, but it will come for him. He should stay calm because I am also very calm."
Neymar scored twice at Old Trafford in a result that may effectively keep under-fire Tuchel in a job, the French giants now firm favourites to advance through to the knockouts.
Comments made by Neymar after the game proved a bigger talking point than Tuchel's future as he talked of his desire to be reunited with Lionel Messi next year.
That has only intensified speculation that Neymar's ex-Barcelona team-mate Messi could be on his way to the French capital, but Tuchel was unwilling to discuss the rumours.
He said: "That is not something I can talk about. I haven't discussed it with Neymar yet, either. I have a lot of respect for Barcelona and for Messi so I will not comment."
PSG make the trip to Montpellier on a two-game winless streak in the league, following up a 3-2 away defeat to Monaco with a 2-2 draw at home to Bordeaux last weekend.
The reigning champions have not lost two successive away games in the top flight since December 2016, with one of those defeats coming at Stade de la Mosson.
Indeed, Montpellier have won two of their last four home Ligue 1 games against PSG, but Tuchel suggested the visit of Basaksehir next week takes priority for his side.
"We will look to respond but we have to accept that we also have a very important game on Tuesday," he said. "I need to find a solution to my team selection.
"It's always tough for us against Montpellier. That is something we need to change, while accepting we have another game on Tuesday.
"We have to accept that for this match there will be decisions made with Basaksehir in mind."
PSG, who announced on Friday that teenage defender Timothee Pembele has signed a new deal until 2024, will definitely be without Pablo Sarabia, Mauro Icardi and Juan Bernat this weekend, while Julian Draxler will be assessed.