The coach has once again selected the midfielder for his squad ahead of the Euro qualifier double-header with France and Iceland next month.
It was an easy decision for Sbragia, who has been impressed by the talented 20-year-old playmaker who has been loaned back to Inverness Caley Thistle.
He said: “I think he has always had ability and talent. It was just about the time when that would all come together. That is gradually happening and he is reaping the benefits of it.
“John Hughes, his boss in Inverness, has done extremely well for him. And the fact he is playing continued first team football is a big plus for him.
“In some cases, players will play one week and then not again for two or three weeks. But Ryan is playing week in, week out.
“I think he has a great chance of playing for Celtic as well, with the form he is in. But he is at Inverness just now and I think he is focused on that. He wants to keep doing extremely well for them and be in this Under-21 squad.”
Sbragia added: “We had a chat on the Friday before the Northern Ireland game about signing for Celtic because it had been a great week for him, albeit a difficult week in a way.
“But he dealt with it. Mentally, he was right. When we spoke to him, there was never any doubt about him wanting to play, or making an excuses.
“That said a lot about him and the great thing for me is that he wants to play for Scotland.”