A deleted scene, from Anthony's party in II, shows Gardner Shaw asking Michael for Sonny's daughter Francesca's hand in marriage. You see in the background a hulking lad in a plaid sports coat. That's Sonny's son, Santino. He's not identified in the deleted-scenes compendium in the three-DVD set, or in the chronological Trilogy that showed on HBO a few years ago. But, a snippet of video, at ~2:15, which was included in the "Saga" version shown many times on US cable TV, shows Michael saying to him, "Santino, how's the football ?" "Fine, Uncle Michael," he replies. Check it out:

https://www.dailymotion.com/video/x42ul2o