The German shot-stopper arrived at Camp Nou this summer from Borussia Monchengladbach.
But after only a few pre-season matches, the Blaugrana have revealed that the youngster has picked up a knock at the club’s training base.
Luis Enrique’s men admitted via a statement on their official website that medical tests had confirmed that Ter Stegen has a ‘lumbar contortion’.
However, the Catalan outfit have refused to determine how long the injury will keep him out for.
Ter Stegen is Barcelona’s second summer signing to be injured as the club also announced that defender Thomas Vermaelen will be out with a hamstring injury, despite passing a medical at the weekend.
The Belgium international completed a move from Arsenal to Camp Nou on Saturday, but the Blaugrana have revealed that the 28-year-old will be out for an indefinite amount of time after picking up the knock in Brazil.
“The first-team player Thomas Vermaelen has a hamstring injury in his right leg that he sustained in June during the World Cup,” a statement on the Barca website read.
“The player will undergo physiotherapy. His return to regular training action depends on the evolution of the injury.”