Dembélé, now 25, joined Barcelona in 2017 on a then club-record transfer from Borussia Dortmund that with variables was set to reach 147 million euros.
Xavi Hernandez has opted to stick with the talented 24-year-old despite reinforcements -- Adama Traoré, Pierre-Emerick Aubameyang and Ferran Torres -- signed in the winter transfer window.
Barcelona president Joan Laporta said on Tuesday the deal to sign Aubameyang was sealed a minute before the transfer window deadline ended on Monday night.
Aubameyang arrived in the Catalan city earlier in the day to finalize negotiations with Barcelona after being stripped of the captaincy at Arsenal for disciplinary reasons.
Barcelona's Ousmane Dembele out injured again in first match since returning from a five-month absence
Dembele suffered a thigh injury in Barca's 1-0 win away at Dynamo Kiev in the Champions League on Tuesday.
Against Celta, Barcelona will likely be without injured defender Gerard Pique, but the club's coach Sergi Barjuan will be able to count on recovered winger Ousmane Dembelé.
Coutinho, who arrived from Liverpool in January, and Dembele, whose debut season in Spain has been thwarted by fitness problems, are the new additions.
Spanish sports daily Marca claim Dortmund can write off at least a quarter of the expected bonus due to Dembele's injury.
Barcelona hope record signing Dembele could be back in action in three and a half months after successful surgery.
Just when Ousmane Dembele was getting used to his role as Neymar's replacement, the young forward was struck by a thigh injury that will keep him sidelined for up to four months.
Barcelona's record signing Ousmane Dembele will be out of action for up to four months due to a hamstring injury he suffered at Getafe.
For all Barcelona's off-field problems, on the pitch they can still rely on Lionel Messi to iron out most difficulties.
The Catalan giants splashed out on Demeble to fill the gap left by Neymar's world record 222 million-euro move to PSG.
The 20-year-old France striker, signed by Barcelona to replace Neymar is expected to make his debut in the Catalan derby against Espanyol this weekend.
Dembele brought an end to protracted transfer talks by agreeing a five-year deal with Barcelona worth 105 million euros.
Reports claim the Germans want 130 million euros for the player they paid Rennes 15m euros for last year.
Dembele was suspended the same day when Dortmund announced they had rejected Barca's opening offer for the France international.
Borussia Dortmund suspended Ousmane Dembele after he missed training without permission as he wants to force a transfer to FC Barcelona.
Borussia Dortmund have rejected an "unacceptable" offer from Barcelona for 20-year-old winger Ousmane Dembele, the Bundesliga club said on Thursday.