The champions have been monitoring Henderson since the start of the season, having been sounded out by scout Bryan Robson, a former player and youth team coach at Sunderland.
Sunderland boss Steve Bruce knows he'll have a fight on his hands to hold on to his promising midfielder, but says he'll do whatever it takes to keep him at the Stadium of Light.
“I think we've given him two contract extensions already and he can have 32 if he wants,” said Bruce.
The indications are that Henderson will be called up to the England senior squad for their friendly against France next month, and Bruce is not surprised.
“I've read that Fabio Capello is going to bring one forward for the France game and apparently the London boys are saying it's him. I don't know if that's true, but it wouldn't surprise me.
“It's quite refreshing in this day and age to find a young kid who wants to train and play, and who thinks properly. From the moment I clapped eyes on him he jumped out like no other player here.
“He's absolutely, completely devoted to football and I hope he stays that way.
“If he does he's got the world at his feet and I don't often say that about a young player. I'm very, very confident of that because of the way he is.”