Barcelona have confirmed Ousmane Dembele is set be out of action between "three and a half months and four months" after the forward ruptured his tendon on his left thigh in his side's 2-1 victory over Getafe.
The France international moved to Camp Nou from Borussia Dortmund for a club-record deal worth €105m (£92.6m, $125.4m) plus €40m (£35.3m, $47.8m) in add-ons. He made his debut in his side's 5-0 win over Espanyol, when he came off the bench.
Dembele was handed his full debut in the Champions League win over Juventus and days later, he made his first start in the league against Getafe at the Coliseum Alfonso Perez. However, he lasted only for 29 minutes before being forced off the pitch due to an injury.
Barcelona revealed the extent of the injury and the 20-year-old will go under the knife as he will be operated on by Dr. Sakari Orava in Finland this week.
A statement on Barcelona's official website read, "The tests have come back following first team player Ousmane Dembélé's injury in the 29th minute of the Getafe match."
"Unfortunately, he has ruptured the tendon in his femoral bicep in his left thigh. The player will be operated on by Dr. Sakari Orava in Finland this week. He is expected to be out for between three and a half months and four months."
With the former Dortmund expected to be out of action for three and a half months, it is unlikely that he could feature for Barcelona once again in this calendar year.
Dembele became the second most expensive player after Neymar. The Brazil international left Barcelona and made a switch to Paris Saint-Germain for a world-record fee of €222m (£200m).
His injury setback will be a massive blow for Barcelona manager Ernesto Valverde. The former Athletic Bilbao boss now has the option of Gerard Deulofeu and Paco Alcacer as the only options up front to play with Lionel Messi and Luis Suarez.