The Hornets are said to be keen on the teenage left-back.
The Hornets are said to be keen on the player by the Walsall Advertiser.
They have apparently joined the race along with Leicester City whilst Manchester United, Arsenal, Liverpool and Tottenham Hotspur are all said to have also paid a keen interest in his development this term.
Watford have been utilising Nathan Ake, on loan from Chelsea, at left-back whilst Jose Holebas has also been involved on occasion.
He was linked with a move to Marseille the other week by the press in Greece so it would make sense that Watford consider their options.
Plus there is the fact that Henry is a top talent that most of the Premier League players should be keeping tabs on.
He has been compared to a young Ashley Cole as he does both the defending and attacking parts of the game well and has been a star in Walsall's surprising League One campaign.
Henry has played 24 times this season for the Sadlers and has scored two goals.