The 26-year-old Mexican has failed to nail down a first-team spot at Old Trafford and was further marginalised during David Moyes' managerial reign last season, making just six Premier League starts.
He may well be eager for a move, and Atletico boss Diego Simeone confirmed his interest in signing the striker as he looks to replace the departed Diego Costa, as per AS: "The technical department are handling it. Like any other player who we are interested in, Hernandez has a chance of arriving before the transfer window closes."
Furthermore, new Red Devils boss Louis van Gaal seemed to suggest Hernandez may not be a United player for much longer when questioned on the subject after his side's victory on penalties over Inter Milan on Tuesday, as per Richard Tanner of the Daily Star.
Van Gaal simply commented: "I can't answer as he is a United player at the moment."
Despite his lack of playing time last season, Chicharito still managed to bag four goals and three assists in the English top flight, as per WhoScored.com, and he is a proven goalscorer at the top level.
With Robin van Persie and Wayne Rooney likely to take the starting roles upfront under Van Gaal, Hernandez would be wise to seek a move, and he would be a fine addition to the Atletico squad.
Like David Villa did for the La Liga champions last term, Hernandez has the ability to snipe around the box and pick up crucial goals due to his instinct from close range.
Meanwhile, speculation is mounting concerning the arrival of another forward at Old Trafford, with Edinson Cavani rumoured to be making the switch from Paris Saint-Germain.
The Ligue 1 champions revealed their new away kit on Monday, and the absence of Cavani from the promotional material has set tongues wagging, as per Bleacher Report UK:
The Paris club have denied that Cavani is for sale, with speculation linking the former Napoli striker to Manchester United beginning in the January transfer window.
At that point a move failed to come to fruition, though it is believed that Manchester United are still interested in acquiring the striker.
Cavani would be a marquee signing for United, but he would be in direct competition with the likes of Rooney and Van Persie for a first-team spot.
Having been overshadowed by Zlatan Ibrahimovic at PSG, as per Sky Germany's Jan Aage Fjortoft, it seems unlikely he would wish to endure the same scenario at United:
Furthermore, added to their strike duo, United's problems are not specifically in attack—the likes of Juan Mata and Ander Herrera also offering genuine quality.
It is in midfield and defence where the Red Devils lack world-class talent, and they would do well to focus on those departments before splashing out on a likely expensive deal for Cavani.