Miguel Herrera has decided to leave Javier Hernandez out of his Mexico squad so that he can sort out his future.
Sky Sports understands that Dinamo Zagreb striker Duje Cop is attracting interest from clubs across Europe.
Press Association Sport understands the 27-year-old Senegal international has rejected the club's latest offer as they attempt to negotiate out the release clause contained in his initial contract.
Despite concerted speculation during the summer, no potential suitor activated the £7.5million get-out which could have lured the former West Ham frontman away from St James' Park.
However, while supporters heaved a sigh of relief that last season's leading scorer would be staying on Tyneside, manager Alan Pardew revealed that the clause would become active once again next month.
The Magpies have been locked in negotiations with Ba's representatives for some time, but there is understood to be a significant gap between the wage deal the former are prepared to offer and that which the latter are willing to accept.
Newcastle are hopeful that the player, who has scored eight times to date this season, is happy to stay and he too has given little indication that he is looking to leave.
Pardew will hope for a breakthrough if he is to avoid a month of waiting anxiously to see if the former Hoffenheim player will remain within his grasp by the end of it.