Neymar, 29, has been sidelined since picking up the injury in the French Cup win over second-division side Caen on Feb. 10.
The Brazil international returned to light training a few days ago, but PSG confirmed Tuesday that this week's second leg against Barca in the round of 16 of the Champions League comes too soon.
"It's not a decision, it's that Neymar cannot play," PSG manager Mauricio Pochettino said at his prematch news conference. "It's a reality, a fact, not a decision. He's unable to compete at the moment.
"He's made a huge effort to be back for this game, but not just for this game, to be back as soon as possible. He's working hard.
"It's a shame, because he was excited about playing this game, but he's also excited about playing for PSG and helping us achieve our objectives in all competitions. Hopefully he's fit soon to help the team. It's difficult because he hoped to be back, but he still needs a few more days."
Sources have told ESPN that Pochettino considered adding him to the squad but didn't want to take any risks, and Neymar agreed with the decision.
Neymar has regularly suffered injuries at this stage of the season, missing Champions League eliminations against Real Madrid and Manchester United in 2018 and 2019, respectively, with fitness issues.
However, he was fit for the latter stages of last year's competition, helping PSG reach the final, where they were beaten 1-0 by Bayern Munich.
PSG say Spain left-back Bernat is "continuing with his recovery and individual work," while on-loan Everton striker Kean remains in self-isolation due to COVID-19.
For Barcelona, defender Ronald Araujo trained on Tuesday but has not been passed fit to travel to Paris. He remains on a lengthy injury list that also includes Gerard Pique, Sergi Roberto, Philippe Coutinho and Ansu Fati.
Information from ESPN's Julien Laurens has been included in this report.