Barcelona's new goalkeeper Wojciech Szczesny will not make his debut against Alaves on Sunday and will instead have to wait until after the international break.

The club signed the Pole as a free agent on Wednesday, with the goalkeeper reversing his decision to retire so he could come to the team's aid following Marc-Andre ter Stegen's season-ending injury.

Ter Stegen suffered a serious knee injury against Villarreal last month, and Inaki Pena has featured in the last three games for Barcelona, most recently keeping a clean sheet in their 5-0 win over Young Boys in the Champions League.

And it looks like Pena is set to start between the sticks against Alaves, too, with Hansi Flick confirming that Szczesny is not yet available for selection.

"Szczesny is in good shape and, with his experience, character and quality, I think he is the very best option for the club," Flick told reporters.

"It's very good to have him, he will help us a lot, but he is not with us against Alaves.

"I am sure after the international break Szczesny will be an option for us. For him also, to play for Barca will be great. We will see how he is doing in training. We have a lot of time."

The Catalan side have a tough run after the international break, hosting Bayern Munich in the Champions League three days before visiting Real Madrid in LaLiga on October 26.

They are in a strong position though, sitting top of the table heading into their match against Alaves, though did suffer their first loss of the domestic season against Osasuna last weekend in a 4-2 defeat.

With 25 goals to their name already, they have made their best scoring start to a single campaign since 2016-17 (26).

However, Flick admitted his decision to rest key starters had an impact in that loss, and accepted the players would not like his choices.

"It's normal to get angry, everyone wants to play more. Those changes had to be made. It's a decision that they have to accept, and they did," he added.

"Lamine Yamal [a 59th-minute substitute against Osasuna] complained that he wasn't receiving many balls, but now he can work on fixing that.

"We have to avoid the many mistakes we made at Osasuna. We need to have more control and possession. It is going to be a high-intensity game at Alaves."