Robert Lewandowski

Borussia Dortmund striker Robert Lewandowski has put both Manchester United and Chelsea on transfer alert, after admitting he could leave Germany at the end of the season.

"I don't set myself any limits. I don't know what will be after this season. I can't and don't want to rule out anything. This would not be professional," the striker told German newspaper Bild. The player has two years left on his Dortmund contract and the Bild report values him at approximately £24m.

The 24 year old Polish international enjoyed a reasonably impressive 2012 European Championship in his homeland, starting all three games and scoring in the group stage game against Greece. He picked up the Man of the Match award in that game for his contributions. Lewandowski, who plays as an out-and-out striker, has 15 goals in 45 appearances for the national team.

The striker's performances at the summer's tournament, and his record with the Bundesliga champions - he netted 30 times last season - meant he attracted attention from United, Chelsea and even Arsenal. The player then fanned the transfer flames by admitting he would welcome a move to the Premier League. Predictably, the club was not very happy with the idea of selling yet another star player (they lost Turkish international Nuri Sahin to Real Madrid last season and Japanese playmaker Shinji Kagawa to United earlier in the summer).

The Germans categorically refuted the idea of selling their player, with club chief executive, Hans-Joachim Watzke telling German media sources he would not entertain any bids.

"It doesn't matter what's being said. I don't know how often I have to repeat this, but Lewandowski will definitely stay with us. There have not been any official approaches," he emphasised.

However, despite the assertion, Watzke also had to field interest from the Blues and the Gunners. Chelsea, the Daily Mail reported, made an approach earlier in the summer but were met with an asking price in excess of £35m. Arsenal, meanwhile, were reportedly considering him as replacement for Robin van Persie. However, given Arsene Wenger has already signed Lukas Podolski and Olivier Giroud, it is unlikely he will move for Lewandowski now.

Chelsea could revive their interest but other reports link them with a £48m bid for Atletico Madrid striker Radamel Falcao. That leaves United, who could have money to spend and a place in the team, if Portuguese forward Nani's £25m move to Zenit St Petersburg comes off.

Finally, there may even be interest from within Germany, after reports indicated Bayern Munich could move for the player. When pressed for a comment on that front, Lewandowski would only say Bayern were a big club and any offer from them would always be interesting.