Barcelona coach Hansi Flick backed reserve goalkeeper Inaki Pena to replace stricken team-mate Marc-Andre ter Stegen on Tuesday, but also said the club must discuss if they will sign a replacement.

Germany international Ter Stegen was taken off with a ruptured knee tendon against Villarreal on Sunday and is likely to miss the rest of the season after undergoing surgery.

Pena, who stepped in for Ter Stegen last season when he was sidelined with a back injury, is poised to start in goal against Getafe on Wednesday in La Liga.

"First of all Inaki is doing really well, in pre-season and training, he's also a professional goalkeeper, he trained very hard for that," Flick told a news conference.

"For a second goalkeeper it's always difficult to be focussed but from what I can see he's absolutely focussed and he's ready to play.

"We have confidence in him but we also have to see what we are doing (about the situation)."

Pena, 25, conceded 32 goals in 17 matches across all competitions last season, keeping only three clean sheets.

Besides Pena, Barcelona have goalkeepers Ander Astralaga, 20, and Diego Kochen, 18, who is currently out injured.

Barcelona are able to sign a free agent to replace Ter Stegen, with Spanish media linking former Real Madrid goalkeeper Keylor Navas with the league leaders.

"We will talk about (what to do) later, because behind (Pena) we have only really young players and if something will change, we have to be careful about that," continued Flick.

"We have no pressure now, we'll see what happens and we'll speak together, also with (goalkeeping coach Jose Ramon de la Fuente) because this is important for me... He's the first person I will speak to and we will see."

Barcelona have a perfect record in La Liga after six games and 17-year-old starlet Lamine Yamal has been in dazzling form, playing almost every minute of the campaign to date, scoring three goals and setting up five.

"I think he could be the best (player) in the world in the future, 100 percent," said Flick, who argued Spain's Euro 2024 winning star is not in need of a rest.

"We have all the data from the players, at the moment he doesn't need a rest -- he's doing well," added the coach.

"What he's doing this season is really unbelievable, also the other players and we have to continue this performance."