Manchester United midfielder Shinji Kagawa could be heading out of Old Trafford.Reuters

Manchester United midfielder Shinji Kagawa could soon be on his way to Atletico Madrid, with the Spanish champions reportedly willing to pay £14m for the Japanese star.

Kagawa has been linked with a move away from Old Trafford since falling behind Juan Mata in United's midfield pecking order.

The Japan international has largely been deployed from the left-hand side during his tenure at United, despite flourishing through the middle for German side Borrusia Dortmund.

The 25-year-old has made 56 appearances and scored six goals for United since Sir Alex Ferguson signed him in 2012, and won the Premier League title in his first season in Manchester.

But his playing time has been limited to being second fiddle to Danny Welbeck and Mata as United underwent a tumultuous campaign under David Moyes.

Now, The Express reports Diego Simone's Atletico are preparing to swoop for Kagawa, with reports claiming a £14m bid is in the pipeline.

Simone has watched as La Liga rivals Barcelona and Real Madrid add firepower to their line-ups in an attempt to overhaul Atletico next season.

Atletico president Enrique Cerezo has already ruled out purging the Premier League of talent including United's Javier Hernandez, Arsenal's Santi Cazorla and Chelsea's Fernando Torres, but remains focused on strengthening the title-winning side.

Kagawa has featured in both of United's pre-season victories in America and is likely to get playing time against Real Madrid on Saturday as van Gaal continues his squad rotation policy.

Speaking to United's official website, Kagawa said he was pleased by the way the US tour was going.

"I think I have been training with focus every day. Pre-season is important to develop my physical strength," he said.

"I learn a lot from training as we have a new manager with new tactics and a new formation. I am working to get myself into shape. It is good that I have been doing so without picking up any injuries."