Sule is in the final year of his contract and as things stand, he is free to discuss a pre-contract with clubs outside Germany from January onwards.
The German champions do not want to lose him and are keen to see him sign a new contract to extend his stay at the club beyond next summer.
The Bavarians have offered terms to him but so far the negotiations have not led to an agreement.
And Salihamidzic conceded that the talks have been difficult due to the nature of his contractual situation at Bayern Munich.
He insisted that the club are doing their best to convince the player to continue at the Allianz Arena.
The deal-maker told DAZN: “He has an expiring contract, the talks are not easy.
“[We are] doing our job as well as possible.”
Newcastle are exploring the possibility of taking Sule to St. James’ Park in the future.
They have the funds to offer a bumper contract, which could trump anything he could earn at Bayern Munich going forward.
