After the club made the announcement, it was reported that Lionel Messi and his wife Antonela Roccuzzo welcomed their third son, Ciro.
The pair, who got married last summer in their native Rosario, Argentina, already had two sons: five-year-old Thiago and two-year-old Mateo.
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Messi, who scored his 600th career goal a week ago, will be replaced by Colombian defender Yerry Mina in the line-up.
It is the first time this season that La Liga's top scorer with 24 goals, is not on the squad for a league game. He has started 26 of Barca's 27 games, coming off the bench once against Espanyol.
The Argentinian posted a photo of the new baby on Instagram with the caption: "Welcome Ciro! Thank God everything went perfect. Mom and he are very well. We are super happy!!!!!"