The midfielder is not involved at Wembley today as his partner gave birth on Saturday.
Speaking to TNT Sports ahead of the 3pm BST kick-off against Crystal Palace, Slot said: “Ryan Gravenberch became a dad last night.”
Four of the Reds’ summer signings – Hugo Ekitike, Jeremie Frimpong, Milos Kerkez and Florian Wirtz – start this afternoon and the head coach added: “Ideally you want to play the best possible game you can play.
“But we also know how difficult it is to play that game against Palace because they are here for a reason: they beat [Aston] Villa in the [Emirates FA Cup] semi-final and [Manchester] City in the final.
“And at the end of the season, Arsenal and us were not able to win against them in our own stadiums. We know how good or how smart it is to keep the team together because that’s what we did last season and we know the end result.
“Palace has exactly the same team playing for them today that played for them throughout almost the whole of last season. So, a big challenge ahead of us.”
