The Catalan giants have been hit with the news that their first-choice stopper Marc-Andre ter Stegen will be absent for the rest of the season due to a severe knee injury.
Pena has started Barcelona's last two matches in Ter Stegen's absence, and the 25-year-old will again be between the sticks for Saturday's La Liga contest against Osasuna.
The Catalan club are preparing to bring in another goalkeeper, though, with Szczesny set to arrive on a free transfer, having departed Juventus over the summer.
Szczesny made 35 appearances for Juventus during the 2023-24 campaign, but his contract was mutually terminated over the summer, with the goalkeeper expected to retire.
Szczesny is set to sign a one-year deal at Barcelona
However, the former Poland international is now set to pen a deal at Camp Nou for the remainder of the season, with the move potentially being confirmed before the end of the weekend.
The 34-year-old will allegedly be paid around €3m (£2.5m) for his efforts this term, but according to journalist Matteo Moretto, there are no guarantees that he will be the number one.
Moretto claims that Szczesny is targeting the starting role, but he has not been made any promises and understands that he could be the back-up to Pena if the Spaniard continues to impress.
Speaking during his press conference on Friday, Barcelona boss Hansi Flick insisted that Pena has the quality to be a starter for the club throughout the campaign.
Flick has backed Pena ahead of goalkeeping arrival
"Yes, he can be (a starter all season). He's working well. It's very good the confidence he can have game by game. We have to wait," the Barcelona boss added.
"Inaki Pena has been involved in all the meetings and all the work we have done. In the last game you could see a very good connection between Inaki and the teammates. He is here to improve and tomorrow is another step forward."
Pena has been with Barcelona since 2012, progressing through the youth system at the club before making his debut for Barcelona B in 2018.
The former Spain Under-21s international made his first appearance for the senior side in 2022, and he has now represented the club on 24 occasions in all competitions.
Pena featured 10 times for Barcelona in La Liga last season in Ter Steen's absence, and he will be aiming to beat that total during the 2024-25 campaign.