Borussia Dortmund are preparing for the exit of Robert Lewandowski by formulating plans to bid for Aston Villa striker Christian Benteke this summer, according to reports.

Polish striker Lewandowski, who scored all four goals in Dortmund's Champions League semi-final first-leg thrashing of Real Madrid, is expected to be the subject of a bidding war between Europe's top clubs at the end of the season.

Manchester United and Bayern Munich are reported to be favourites to land the 24-year-old, who is supposedly refusing to sign an extension to his contract with the Westfalenstadion outfit that expires in 2014.

According to the Daily Mail, Dortmund sent representatives to watch 23-goal forward Benteke against Chelsea, and they returned to Germany to inform manager Jurgen Klopp that he was capable of replacing Lewandowski.

Premier League duo Tottenham Hotspur and Arsenal are apparently heading the English interest in Benteke, who is valued by Villa at upwards of £20m.