Argentine football captain also the Barcelona forward Lionel Messi became the father of second son Benjamin on Friday night.
Last month Lionel Messi was named the UEFA Best Player in Europe award for the 2014-15 season for helping Barcelona to a Treble of trophies.
Messi missed Barcelona’s training session as he attended the birth with club permission. But he will be in the squad to face Atletico on Saturday.
Coach Luis Enrique told a news conference: “He [Messi] is available to play. He is on the list. The club gave him permission not to train today for personal reasons.”
The Argentina international already has one son with girlfriend Antonella Roccuzzo, Thiago, who was born in 2012.
Saturday’s game will see the last two Primera Division champions square off at the Vicente Calderon stadium.
Both sides have enjoyed perfect starts to the campaign.
Barcelona confirmed their 18 man squad for the game against Atletico is: Ter Stegen, Masip, Rakitic, Sergio, Iniesta, Suárez, Messi, Neymar, Rafinha, Mascherano, Bartra, Munir, Jordi Alba, Sandro, Sergi Roberto, Adriano, Vermaelen, Mathieu.