"Olmo suffered a dislocation of his left shoulder in yesterday's match against Atletico Madrid," Barca said in a statement on their official website.
"After undergoing a series of tests, it was decided to undergo conservative treatment. The estimated recovery time is approximately one month."
The Spanish international suffered the injury after falling after scoring in Tuesday's 3-1 win over Atletico Madrid. The victory moved Barca four points clear of nearest rivals Real Madrid at the top of La Liga.
The 27-year-old has had several injury problems since joining the Catalan club from RB Leipzig in 2024.
Olmo joins a long list of injured Barca players, including Fermin Lopez, Gavi, and Marc-Andre ter Stegen. Olmo sustained the injury just before next week's Champions League match against Eintracht Frankfurt.
