The French winger arrived at Camp Nou to fill the hole left by Neymar in 2017, but recurring injuries and problems adapting have plagued him.
Signed for an initial €105m from Borussia Dortmund, Dembele has managed just five La Liga appearances this season.
And according to Fernando Polo of Mundo Deportivo, Barcelona are willing to let him go for a reasonable offer.
The Catalans still owe €50m to Borussia Dortmund and an offer matching or exceeding that would be accepted.
Quique Setien values Dembele and he could yet stay at the club, depending on whether suitable offers are made.