Borussia Dortmund attacking midfielder Shinji Kagawa will leave the German champions this summer, according to team-mate Mats Hummels.

The Japanese international has been heavily linked with a move to Manchester United this summer as he stalls over a new contract.

With the season not yet over, Kagawa's future is unlikely to be resolved in the near future, however Hummels believes his teammate will leave the Bundesliga this summer.

Shinji Kagawa
Kagawa appears certain to leave Dortmund.

"Shinji is a world class player, but honestly, I don't expect him to stay with us. Otherwise, he would have extended his contract by now," Hummels told Bild.

"However, I'm not scared because we're going to get Marco Reus and we won't be losing any quality."

The 23-year-old has scored 13 goals in 31 games for a Dortmund side who can complete a league and cup double with victory in the German Cup final this weekend against Bayern Munich, who they piped to the Bundesliga title earlier this season.

However, a refusal to agree terms over a new contract has sparked rumours of a move away from Dortmund, with United, who look likely to miss out on the Premier League title, prowling.

Kagawa has 26 caps for Japan and played a role in the Asian Cup win in 2011.

An overhaul of United's squad is likely this summer, with a spending spree mirroring last summer's expected as Sir Alex Ferguson looks to keep pace with Manchester City.

The over reliance on Paul Scholes and Ryan Giggs as well as concerns over Darren Fletcher's long-term availability might force Ferguson into investing in a new midfield this summer.

Tom Cleverley's fitness in his first full season in the United's first-team has restricted his opportunities, while Ji-Sung Park has been sporadically involved.

United are looking for favours going into the final weekend of the season, requiring a win over Sunderland while hoping that relegation threatened Queens Park Rangers can take points off current leaders City.

While the Old Trafford club are looking for their 20th league title, and their 13th in the Premier League era, City are aiming to claim their first domestic title for 44 years.