The 34-year-old will take questions from the press at noon (1000 GMT), Barcelona said in a statement. They will be his first public comments since his departure was announced.
Barcelona president Joan Laporta said on Friday he was not prepared “to put the club at risk” by renewing Messi’s contract, as the club face up to huge financial problems ahead of the start of LaLiga on August 15.
PSG, who bought Neymar from Barcelona for a world-record 222 million euros ($264 million) in 2017, appear favourites to sign Messi according to reports in France.
Broadcaster RMC Sport reported that Messi has informed PSG of his desire to join the club and that discussions were ongoing over a two-year deal with the option of a third season.