Manchester United could be on the verge of losing Japanese ace Shinji Kagawa after just one season at Old Trafford. 

Kagawa's name has surfaced in transfer rumors. As John Edwards of the Daily Mail reports, Borussia Dortmund would fancy bringing their former player back. Kagawa originally left Cerezo Osaka for the German side. 

Given his lack of opportunity with the Red Devils, Kagawa certainly could be tempted to leave. After all, he seems confident that he has the ability to play regularly for United.

Still it was a rough first year for Kagawa, as he received inconsistent playing time.  

Kagawa told FootBrain, via the Express' Ben Jefferson, and passed along this message to new United manager David Moyes:  "For me it was not a good season for United. If Dortmund agrees, I would like to one day return to this team." 

That prompted Borussia Dortmund chief executive Hans-Joachim Watzke to demonstrate again his club's willingness to take back former players. Kagawa now knows that, like on-loan Liverpool midfielder Nuri Sahin last season, he could revive his faltering fortunes under the guidance of Dortmund boss Jurgen Klopp.

However, with a new manager and a new season, there is new opportunity for Kagawa. In a quote provided by Jefferson, Moyes had this to say about Kagawa: 

It was his first season in the Premier League last year. He's a young player so we hope his development continues. I look forward to working with him and hopefully he has a really good season coming up.

The Red Devils have to be careful with Kagawa. He has far too much potential to let him slip away. While he didn't earn a lot of playing time last year, he was productive when he was on the pitch. 

The Japanese international made 20 appearances (17 starts) during United's their title-winning campaign. He also bagged six goals, the fourth highest in the squad behind Robin van Persie (26), Wayne Rooney (12) and Javier Hernandez (10). 

No other player scored more than five goals during Manchester United’s English campaign. 

Kagawa was also disciplined throughout the season, committing only nine fouls in the Premier League (one of the lowest totals for United) and receiving only one yellow card. 

In terms of shots per match, Kagawa produced an average return, firing off 1.1 per 90 minutes. Van Persie had the most, with one of the top totals in the Premier League—3.7 per match.

While Kagawa can improve in this area, he was certainly accurate and registered a 75 percent accuracy rate, not too shabby at all. 

The Red Devils cannot afford to let a player of Kagawa's quality get away.