Ander Herrera
Ander Herrera joined United from Athletic Club in 2014. Getty

Atletico Madrid are said to be "close" to reaching an agreement with Ander Herrera to lure the Manchester United star to the new Wanda Metropolitano as a free-agent once his current contract at Old Trafford expires in the summer.

Spanish publication AS claims that the 28-year-old midfielder has already said "yes" to the move with manager Diego Simeone also keen on enlisting his services.

Herrera won the United player of the year award during Jose Mourinho's first campaign at Old Trafford and was also named man of the match in the Europa League final victory over Ajax.

However, his long-term future with the Premier League giants has been under some scrutiny amid delays in negotiations over a new deal.

Nevertheless, the former Athletic Bilbao star will be free to negotiate a move to another side from January with current contract at United due to expire at the end of the season.

Mourinho's side are said to have been in negotiations with the Spaniard for months after the player was heavily linked with Barcelona in the summer.

Daily Mail reported that United were set to offer Herrera a £120,000-a-week in order to tie him to a new long-term deal.

However, there have not been any update since then and last month Daily Mail claimed that United were expected to trigger an automatic option to extend his deal 12 months further if the talks over a new deal continue to drag on.

Barcelona were said to be monitoring the situation closely but now AS claims that Atletico's interest could be the reason why Herrera has turned down all the approaches from United to tie him to a new long-term deal.

The Spanish publication says that Herrera is not completely comfortable at Old Trafford after seeing his playing time limited following the arrival of Nemanja Matic.

Herrera has recaptured his place in the team following Paul Pogba's injury but AS says that the player is still keen on returning to La Liga to play for Atletico.

Los Colchoneros were unable to sign anyone in the summer due to a Fifa transfer embargo and are expected to break the bank in the coming markets to bolster Simeone's side.

Former Chelsea striker Diego Costa and Spanish international Vitolo have already agreed to join them in January and AS says that Los Colchoneros want Herrera to follow in their footsteps in the summer transfer window.

AS insists that Herrera has already said "yes" to moving to Atletico as free-agent in the summer but United could still block the deal if they activate the option to extend his deal by another year.

In that case, if Herrera really wants to leave, United would have to negotiate a fee with Los Colchoneros or risk losing him for free in the summer of 2019.