The Magpies have a fallback plan if the 20-year-old doesn't move to Tyneside.
Indeed, Mitrovic is very much seen as 'Plan A' but the amount of time it has taken the Serb to commit to Newcastle suggests a deal may not be agreed, with the next 24 hours said to be crucial in negotiations.
As such, the Chronicle report that 26-year-old Bas Dost will be Newcastle's fallback if 20-year-old Mitrovic can't be secured.
Will a deal go through?
Mitrovic has been linked with Newcastle for quite some time but, crucially, so was Georginio Wijnaldum - and he has already completed his move to St James' Park.
The longer any move for the Serbian striker takes, then, the less likely it is to happen, one would assume. Wijnaldum, meanwhile, is an attacking player but not an out-an-out striker, something Newcastle are still in desperate need of.
That said, should the next day or two move in the right direction, Mitrovic may well end up a Magpie - or Bas Dost sounds like a good enough Plan B...