Woodgate joined Liverpool's scouting staff after hanging up his boots in 2016 thanks to a connection with Michael Edwards.
As part of his role, Woodgate recalled watching a number of young talents who have gone on to big things, with AC Milan fullback Hernandez and new Manchester City signing Ruben Dias among those who stood out.
He told Jamie Carragher's podcast: "You get to know all the younger players from around the world like the lad [Marcos] Llorente at Atletico Madrid, the Hernandez brothers who moved to Bayern Munich and Real Madrid - and Ruben Dias at Benfica.
"You do your homework before and sometimes you are given players to watch and you have to do in-depth analysis and then you send it off.
"What is his body position like at the front post when the ball comes into the box? Does he get tight to his man? Does he stay free and go and attack the ball?
"Little things like that and I would clip these things up on my computer - not just on the ball, off the ball too, of what you're seeing.
"I recommended a player who signed for Real Madrid. I absolutely adored him but [Liverpool] decided they didn't want him. He's done OK - he's at AC Milan now. Theo Hernandez - bombs on for fun, and he's a machine."