According to the blue garnet's Twitter account, in addition to Messi, midfielders Sergio Busquets, Philippe Coutinho and Frenkie de Jong returned to the general group, as well as forward Ansu Fati.
At the same time, Messi conducted the first training session under the guidance of the new head coach Ronald Koeman on September 7.
Messi, 33, is a Barcelona graduate and has played in the first squad since 2003.
Together with the club, he won 34 trophies.
He has 634 goals and 285 assists in 731 matches.
After a crushing defeat to Bayern Munich in the Champions League quarter-finals (2: 8), it was reported that he wants to leave the team.
Nevertheless, on September 4, Messi announced that he will remain at Barcelona.
Earlier it was reported that Messi will discuss with Koeman whether he will remain the captain of Barcelona.