Barcelona have revealed that Sergio Aguero is set to be missing for "around 10 weeks" after suffering a calf injury that will delay his start to life at Camp Nou.
The Argentina international only linked up with the Blaugrana at the start of the summer having become a free agent at the end of his contract with Manchester City.
He is yet to be officially registered amid financial struggles in Catalunya, has seen fellow countryman Lionel Messi depart Camp Nou in emotional circumstances and must now wait on a competitive debut for his new club after picking up an untimely knock.
Barcelona said in a statement on the club's official website: "Tests carried out on first-team player Kun Aguero have confirmed a right calf injury.
"He will be out for around 10 weeks."
The experienced South American saw his start to life at Barca delayed by a successful Copa America campaign alongside Messi.
Upon starting training with the Liga giants, he has now been laid low and could be out of action until the middle of October.
If that does prove to be the case, then Aguero could miss nine domestic fixtures.
He will also be absent for the start of group-stage action in the 2021-22 Champions League, as Barca look to chase down major honours without club legend Messi.
The games that Aguero is in danger of sitting out in La Liga come against Real Sociedad, Athletic Club, Getafe, Sevilla, Granada, Cadiz, Levante, Atletico Madrid and Valencia.
Aguero may be back in the fold by the time a first Clasico clash with Real Madrid is taken in on October 24, but he will be seriously short of match fitness and sharpness.
At 33 years of age, injury struggles have become an all too familiar theme for Aguero.
He sat out 17 games for City during his final season at the Etihad Stadium, having previously missed 24 in 2019-20 with muscle and knee complaints.