The Bundesliga giants are ready to let the Ghana midfielder leave this summer.
Lambert could sign the 26-year-old for just £2.5million.
The highly-rated midfielder has also been linked with a return to former club Rosenborg in recent weeks.
Liverpool and Chelsea chasing Turkish star
Liverpool and Chelsea are reportedly showing keen interest in Inter Milan midfielder Hakan Calhanoglu.
The 29-year-old Turkish midfielder has...
Man Utd and Liverpool join chase for Arsenal and Bayern Munich target
Manchester United and Liverpool have entered the race to sign Fulham's standout midfielder Joao Palhinha, joining other top clubs vying for the...
Crouch with predictions ahead of Aston Villa v Arsenal clash
Former Liverpool and Tottenham forward Peter Crouch has made his prediction for the clash between Aston Villa and Premier League leaders Arsenal...
Arsenal join chase for Fulham star
Arsenal manager Mikel Arteta is reportedly considering a move for Fulham midfielder Joao Palhinha.
Arsenal are looking to sign...
Crouch with predictions ahead of Aston Villa v Arsenal clash
Former Liverpool and Tottenham forward Peter Crouch has made his prediction for the clash between Aston Villa and Premier League leaders Arsenal...
Crouch with predictions ahead of Newcastle v Arsenal clash
Former Liverpool and England forward Peter Crouch has made his prediction for the clash between Newcastle and Arsenal on Saturday evening.