Neymar left the ground in tears as he was carried down the tunnel in the first half before the Brazilian Football Confederation (CBF) confirmed the PSG star's absence from the Copa America, which gets underway on 15 June.
Ligue 1 champion PSG released a statement on Friday (AEST), which read: "Neymar Jr. suffered a severe sprain of the outer lateral ligament of his right ankle in Brasilia during a warm-up match for the Copa America.
"Paris Saint-Germain's Brazil striker will be reassessed by the club's medical department within the next 72 hours to define the rehabilitation process and recovery time for the player."
Neymar, 27, was braced for the toughest match of his career midweek amid a rape allegation.
A Sao Paulo state official confirmed to Omnisport on Saturday that a charge has been brought against the PSG forward following an incident in the French capital on 16 May.
Neymar vehemently denies the accusation and posted an Instagram video, in which he claimed the allegations are an attempt to "extort" him.
He is now facing a police investigation in Brazil after publishing intimate pictures of the alleged victim within the social media video.
Neymar netted 15 Ligue 1 goals and 23 across all competitions for French champion PSG in 2018-2019.