The France international received medical clearance to feature in the Champions League clash at Camp Nou after coming through a training session on the eve of the Group F fixture.
Umtiti has been dealing with a knee injury that kept him out of Barca's last three games.
The centre-back was also sidelined earlier in the 2019-20 season with a foot issue; his solitary outing so far came in a 3-0 away triumph over Eibar on September 19.
Asked about Dembele's absence in a news conference on Monday, head coach Ernesto Valverde said that "everyone always has to earn their place" in the Barca team.
The Spanish champions sit top of a group that also includes Borussia Dortmund and Inter.