Chelsea have been told a move for Borussia Dortmund's Pierre-Emerick Aubameyang must be completed this week as the Premier League champions desperately search for a striker to lead their attack next season. With Romelu Lukaku joining Manchester United and Alvaro Morata destined to move to AC Milan, the Gabon international is the Blues' latest target but a deal is far from certain.

Last week reports suggested the forward had emerged as manager Antonio Conte's preferred target but that a fee of €70m would be required to bring him to England, according to Marca. The 28-year-old netted 40 goals in all competitions last season but as he approaches his tender years time is running out to make the move which could define his career.

Dortmund are anticipating the remainder of the summer transfer window to be full of speculation but are hopeful of warning off any further interest in Aubameyang by setting a deadline of this week for any move to be concluded, giving them time to sign a replacement. No offer has been submitted as yet, meaning Chelsea are running out of time to meet the ultimatum set by the Bundesliga giants.

"We have told Auba: 'If you want to move somewhere, and you have a club willing to meet our demands, then come to us and we'll talk.' But this will only apply within a certain time window, which is slowly closing," Dortmund chief executive Hans-Joachim Watzke said, according to The Sun.

"We would clearly need to get a replacement for him, which is difficult to impossible in any event. We will wait for a couple more days, but not for much longer. There are no offers on the table for him so far. Personally I would prefer him to stay with us. But there are a few clubs on this planet where he could clearly earn more money."

Chelsea's summer transfer window plans have been thrown into disarray by the failure to land Lukaku, while Morata is also expected to evade their grasp as he prepares to leave Real Madrid. Diego Costa has been made surplus to requirements at Stamford Bridge and according to Marcel Desailly Aubameyang is the only man available to fill the void in Conte's side.

"Morata, does he fit really? Does he hold the ball, does he have the speed of projection [Conte] is asking for?" the ex-Chelsea defender said, report Goal.com. "So it is a blow for him really [missing out on Lukaku]. For me, Aubameyang will be the best player to adapt to the Conte system."

Pierre-Emerick Aubameyang
Aubameyang scored 40 goals last season and is regarded as one of the hottest strikers in Europe.Getty Images