Samuel, the former Inter Milan and Argentina defender, is currently a member of Scaloni's coaching staff, although his longer-term future remains uncertain.
Scaloni explained that Samuel had been offered a role at Inter under Cristian Chivu but chose instead to stay with the national team for the World Cup.
“Walter has already shown us what the national team means to him when he turned down an offer from Inter and Chivu to be with us at the World Cup,” Scaloni said.
“As well as being fundamental to the team, he is a friend of mine and I want the best for him.”
Samuel's decision highlights the importance Scaloni places on his assistant, who has been part of the coaching structure behind Argentina's recent success.
However, Scaloni acknowledged that Samuel's next career move has not yet been settled and indicated that the possibility of him pursuing a head coaching role remains open.
“The door is always open for him, but there are no updates yet,” the Argentina manager said.
“If he were to leave, it would be a huge loss for us. He is a friend and I wish him all the best.”
Samuel previously enjoyed a long playing career with Inter, where he became a key part of the club's defence, and his potential return in a coaching capacity was therefore a significant opportunity.
For now, however, his future remains unresolved, with Scaloni making clear that Argentina would welcome him continuing his work alongside the national team.