Barcelona will again be missing number one goalkeeper Marc-Andre ter Stegen for Tuesday's Champions League contest with Portuguese giants Porto.

Ter Stegen missed out against Rayo Vallecano in La Liga on Saturday due to a back problem which he suffered during a training session with Germany over the international break.

Barcelona were hopeful that the stopper would be back against Porto, but he has again been left out of the squad, which will mean that Inaki Pena continues between the sticks for the La Liga champions.

Gavi is also absent, with the midfielder picking up a season-ending knee injury while representing Spain over the international break, but Sergi Roberto has recovered from a calf issue to make the squad.

Frenkie de Jong is also included, with the midfielder not suffering any issues after returning from an ankle problem in the 1-1 draw with Rayo in the league last time out.

Youngsters Aleix Garrido and Unai Hernandez have dropped out of the squad, but there is a spot for Marc Casado, who missed out against Rayo due to a suspension.

Barcelona would book their spot in the last-16 stage of the competition if they win against Porto, while a draw would also be enough if Shakhtar Donetsk either draw or lose to Royal Antwerp in the other match in the section.

However, a defeat for the Catalan side, coupled with a win for Shakhtar, would leave the two sides on nine points heading into the final matchday, with Porto then moving onto 12 points at the summit.

"We have to go for the games from the first minute, that's what we are missing, we only react when there is an urgency, in the last minutes," head coach Xavi told reporters during his pre-match press conference.

"We have to react, it's part of the process, we know the way, we have to compete and tomorrow can be a turning point. We have failed in high pressure, in intensity, in mentality. There are many things. But I firmly believe that we will play well again and achieve results, Otherwise I wouldn't be here.

"Here there is always talk of a crisis if you don't win. You always have to win. It's the demand. There is always criticism, it's normal, it is accepted to improve, be more forceful, have a more positive and winning mentality. Barca is the maximum demand.

"The most difficult thing in sport is to win again after having won. That's why individual athletes who don't stop winning and see winning as a drug are tremendously admirable. We have won but we have to win again and be a competitive animal."

Xavi is yet to lead Barcelona into the knockout round of the Champions League, with the Catalan outfit eliminated in the group stage in their last two campaigns.

Barcelona squad vs. Porto:

Pena, Astralaga, Kochen; Cancelo, Balde, Araujo, I Martinez, Christensen, Alonso, Kounde; Pedri, Romeu, Roberto, De Jong, Gundogan, Casado, F Lopez; Lewandowski, F Torres, Raphinha, Felix, Yamal