Chelsea have been told they must double their offer if they want to sign Borussia Dortmund star Robert Lewandowski, a reported target for Arsenal, Tottenham and Manchester United.
The 23-year-old Polish international is one of the most sought-after strikers in Europe at the moment, attracting attention from a host of top clubs, both in England and abroad.
Blues boss Roberto Di Matteo is keen to strengthen his forward ranks at Stamford Bridge with the addition of Lewandowski, and the club are believed to have offered an initial £13million, rising to £17million to secure his signature.
However, Lewandowski still has two years to run on his existing contract with the Bundesliga giants, and his agent Maik Barthel says that whilst interest in his client is high, all offers are some way off his actual valuation.
Speaking to Goal.com, Barthel explained: "Unofficially there are offers from English top clubs. We respect the contract situation in Dortmund and don't want to take part in speculation. A £13 million transfer fee is not suitable."
Sir Alex Ferguson is monitoring the situation as he seeks a replacement for want-away striker Dimitar Berbatov. The Bulgarian could even be offered in exchange as part of a deal taking Lewandowski to Old Trafford.
Meanwhile, as Arsenal's hopes of retaining the services of club captain Robin van Persie look increasingly unlikely, Arsene Wenger could turn to the Dortmund ace as a potential replacement for their preliminary source of Gunners goals.
North London rivals Tottenham could lodge a rival bid for Lewandowski, with Andre VVillas-Boas searching for alternative options to Emmanuel Adebayor, whose wage demands continue to hamper his permanent move to White Hart Lane.
With 22 goals in 34 appearances in the Bundesliga last season, Poland's prolific frontman enhanced his reputation with a series of impressive performances at Euro 2012, and could yet negotiate a lucrative transfer ahead of the 2012-13 campaign.