Mundo Deportivo says Lenglet has decided to take the plunge this summer and make the move to a big club.
The France international's agent has met with Barca GM Pep Segura and technical secretary Robert Fernandez in recent days and agreed terms over a five-year contract. Lenglet will move to the Nou Camp independent of whether Samuel Umtiti stays or leaves.
Barca will now move to pay the player's €35m buyout clause in his Sevilla contract.
At 22, Lenglet did have concerns about his playing chances at Barca, but has been persuaded to make the move after speaking with his agent and advisers.