The 18-year-old, who scored the match-winner in a 1-0 victory against Celta Vigo on Wednesday, limped off just before the break, replaced by Swedish international Roony Bardghji.
In a statement published on social media, the Catalan club said: "The tests carried out have confirmed that first-team player Lamine Yamal has a hamstring injury in his left leg (biceps femoris muscle).
"The player will follow a conservative treatment plan. Lamine Yamal will miss the remainder of the season, and he is expected to be available for the World Cup."
With Barcelona nine points clear at the top of LaLiga, the only competition they remain in, the club seems inclined not to rush their star player back, given it is a World Cup year.
Lamine Yamal has been in sparkling form all season, scoring 16 goals and generating 11 assists in the Spanish top flight, whilst netting a further six in the Champions League.
Injury concerns have been few and far between this season for Lamine Yamal. The winger has suffered two groin injuries that kept him out for a combined 23 days, playing a total of 51 matches for club and country this season.
He will miss six Barcelona games to end the season, including El Clásico against Real Madrid on May 10th, in what could be a Catalan coronation at Camp Nou.
He was also a pivotal member of Spain's EURO 2024 triumph as a 16-year-old, in what was a breakout tournament for the teenager.
Paired with Nico Williams, the two were deadly on the flanks, as Luis de la Fuente's men lifted their first piece of international silverware since EURO 2012, beating England 2-1 in the final.
Despite being just 18, Lamine Yamal already has 25 caps for his national side and will be a key part of their team this summer.
Spain begin their campaign at the 48-team World Cup on June 15th against Cape Verde in Atlanta, followed by Group H clashes with Saudi Arabia and Uruguay.