Marco Verratti sprained his ankle during Paris Saint-Germain's 9-0 demolition of Guingamp on Saturday, medical checks have confirmed.
"The MRI has confirmed a sprained left ankle without any other injury," PSG said in a statement on Sunday.
"New checks early in the week will help define the length of his absence. "
Italy international Verratti left the pitch after 13 minutes of the match after a Guingamp player stepped on his ankle and PSG boss Thomas Tuchel was downbeat postmatch, suggesting the injury could be a bad one.
"I think that it is serious," Tuchel said. "Really, it is the worst thing that could have happened to us."
At his news conference he added: "We have several options in midfield -- Marco with Marquinhos, Dani [Alves] with Marco, Dani with Julian [Draxler], or Dani with Marquinhos. However, without Marco, and with Presnel [Kimpembe] still injured, we only have one choice."
Tuchel was blown away by his team in front of goal and reserved special praise for Alves after his shift in midfield.
"I do not think that I have ever seen a 9-0 league win -- we put in a very complete performance," Tuchel said. "Dani's mentality and energy were exceptional. He can play short, as well as fast, and can also provide assists. Dani can help us in midfield as he has the mentality and bravery to do so."
Despite the comprehensive nature of the win, Mbappe told beIN Sports that "wins like this are never trivial -- last week's defeat to Guingamp proves that," while Gianluigi Buffon suggested that there was extra motivation after PSG's recent Coupe de la Ligue exit at home to Saturday's visitors.
"It was a special match as they knocked us out of the Coupe de la Ligue," the Italy international told beIN Sports. "We wanted to show that we are still the best team in France.
"In football, it is very important to respect your opponent. When you respect your opponent, you score when you can score -- that is what we did."
However, Guingamp's Etienne Didot branded the collective performance as shameful and "ridiculous."
"We made people happy with our Coupe de la Ligue win here, as well as the win over Rennes, which we enjoyed, but we must also be able to realise when we should be ashamed and look ridiculous," he said. "We were ridiculous here and we can be ashamed of what went on. We are ashamed right now, totally ashamed."
Guingamp coach Jocelyn Gourvennec likened his team to a youth side and blasted the "beginners' mistakes" that he saw just over a week after a deserved Coupe de la Ligue win in the capital.
"We lost in every aspect of the match," he said. "We were drowned, and we made beginners mistakes -- it felt like I was watching a Gambardella [youth] team up against a Ligue 1 side.
"We won here 10 days ago, and I do not think that we stole that result. Ten days later, we were quickly punished."
PSG travel to Manchester United for their Champions League round-16 first leg on Feb. 12.
Information from Reuters was used in this report.