The four-time world player of the year was substituted at half-time of the 2-2 draw against the Parisians and will miss Saturday's Liga clash with Mallorca.
However, he could yet return against PSG depending on how he recovers over the coming days.
"The medical services of the club have confirmed after carrying out tests that Leo Messi has suffered a hamstring injury in his right leg," said a statement on the club's website on Wednesday.
"He is out of the league game on Saturday and his evolution will decide his availability for the games that follow."
Pics: Prabhas, Tamannaah Bhatia at 'Baahubali 2' first look launch at MAMI
'Ae Dil Hai Mushkil' photos: Aishwarya, Anushka, Karan get candid at MAMI
Photos: Huma Qureshi, Neha Dhupia and other celebs at MAMI
Photos: Amy Jackson, Daisy Shah at Mumbai airport
Photos: Sridevi, Irrfan and other celebs at 'Mughal-e-Azam' screening