Barca announced the 22-year-old France international has sustained a complete proximal hamstring tear in his right leg and it is reported he will sit out the rest of the season.
INJURY UPDATE | Tests carried out on Ousmane Dembélé today have confirmed that he has a complete proximal hamstring tear in his right thigh. In the next few hours a decision will be made on the treatment to be followed for his recovery. pic.twitter.com/fk7KgzaMC6— FC Barcelona (@FCBarcelona) February 4, 2020
Dembele has been plagued by injuries since arriving at Camp Nou from Borussia Dortmund for an initial €105million in August 2017.
The latest injury came as he stepped up his return from a right hamstring problem that has sidelined him since November.
In total, injury problems have forced Dembele to miss 59 matches for the Catalan giants. That is equivalent to 40.4 per cent of the games Barca have played in LaLiga, the Copa del Rey, the Champions League and the Supercopa de Espana since his arrival.
The winger has played just 31.4 per cent of the total minutes that would have been available to him across all competitions had he not suffered any injuries at Barca.
Based on his transfer fee alone, he has cost the club a whopping €1.4million per match.
Luis Suarez is out until May after undergoing knee surgery. Carles Perez was allowed to join Roma on loan with an option, that could become an obligation, to buy. Abel Ruiz will spend the rest of the season at Braga and then complete an €8m transfer there. Francisco Trincao will not arrive from Braga in a €31m switch until the end of the campaign. Barca reportedly pulled the plug on a loan deal for former Villarreal striker Cedric Bakambu before the transfer deadline.
With Dembele set to miss a significant period of time, Barca are hamstrung in the attacking department and it is a mess of their own making.
Head coach Quique Setien had been counting on Dembele's seemingly imminent return to bolster his attacking options after the club failed to bring a new forward in during the January transfer window.
"The transfer market did not give us anything, but we will also recover Dembele," Setien said following a 5-0 victory over Leganes in the Copa del Rey last week.
"He is a player who has specific attributes and I think he can give us a lot. He feels comfortable out wide and we will try to take advantage of that.
"I'm sure he will give us a lot with the potential he has and will demonstrate the great player he is. Dembele is going to be amazing."
Barcelona have instead looked to their B team to improve their depth, with Kike Saverio and Rey Manaj added to their Champions League squad for the rest of the campaign.
Ecuador-born striker Saverio won the UEFA Youth League in 2017-18 and is strong on both feet but has only scored four goals in 34 appearances for Barca B.
Former Inter attacker Manaj joined the second string for an initial €700,000 from second-tier side Albacete in January. He scored his first goal for the club a 2-1 win over Prat on Sunday, but his second outing ended before half-time as he was sent off for two bookable offences.
Although Ansu Fati notched a double in the 2-1 victory over Levante on Sunday, it has been reported Barca will look to sign a free agent from outside Spain as emergency cover.
Regardless of their next move, Barca will be at a significant disadvantage as they seek to retain their LaLiga title and push on in the latter stages of the Champions League.