The Serbian star has scored 17 goals for the Magpies since arriving from Anderlecht but is struggling to fight his way back into the side after picking up a three-game ban at the start of the season.
There have also been reservations about his work rate for Rafa Benitez’s men and the Spaniard could be set to cash in when the transfer window opens, if he receives a big enough offer for the player.
Reports now claim that Brighton are leading the race after watching him in action on Friday night.
Seagulls boss Chris Hughton sent a scout to watch the World Cup qualifier between Austria and Serbia in Vienna, a game the hosts won 3-2.
Speculation has been rife over who the target was and Mitrovic's name was mentioned in the lead up, but now it appears that the Magpies striker was the player under the microscope.
Hughton is in desperate need of more firepower and Mitrovic now looks to be high on his list of targets ahead of the transfer window re-opening in the new year.