Robert Lewandowski is proving to be one of the most sought-after signatures in world football

ESPN understands Barcelona have made preliminary contact with Robert Lewandowski's representatives as the race for the Borussia Dortmund forward escalates.

Manchester United had also recently been given encouragement by the 25-year-old's camp that a deal may be possible and retain significant interest, but are understood to now be concerned about Barcelona's clout.

Given Lionel Messi's status as Barca's talisman over the last two seasons, as well as the need to slightly alter the dynamic of a team in danger of growing stale, the Catalans are seeking to add extra spark and angles to their forward line - with this summer's purchase of Neymar the first step.

They are now considering a move for Lewandowski that would potentially give them their strongest collective forward line since the Messi-Samuel Eto'o-Thierry Henry trio of 2008-09.

Meanwhile, Lewandowski's agent has played down a report in German tabloid Bild that suggested the striker's relationship with Dortmund had reached breaking point.

Dortmund announced at the weekend that Lewandowski, who has been linked with a move away from the club, will not be allowed to join Bundesliga rivals Bayern Munich this summer.

It has since been suggested the stance has soured matters between the Poland international and his current side, with Bild reporting that he would prefer not to return for pre-season.

However, on Thursday, German news agency SID quoted Lewandowski's agent Maik Barthel as saying: "We don't know anything about [the Bild report]. Besides, all that needs to be said from our side has already been said."

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