"I still believe in Scepovic because I know he has potential but we can't help him if he doesn't want to help himself and this will be the last game he plays for Serbia if he doesn't change his attitude," Mihajlovic said ahead of Wednesday's friendly against Colombia in Barcelona.
"I get the impression the boy thinks he is doing someone a favour whenever he is on the pitch and he should look up to his junior strike partner Aleksandar Mitrovic, who has set an example of how one should cherish playing for the national team," Mihajlovic told a news conference.
"I don't care if Scepovic scores against the Colombians or not. What I want is 100 percent effort from him and it's now up to him which way his career goes."
Scepovic, who has failed to score in three international appearances, is also out of favour at Serbian champions Partizan Belgrade and was left out of Saturday's 4-3 league win over Novi Pazar after an incident involving a fan following the team's Champions League elimination.
The leader of a die-hard section of Partizan fans vaulted over a barrier behind one of the goals after the team's 3-1 aggregate defeat by Bulgarian side Ludogorets last Tuesday and tore the captain's armband off Scepovic.
Teenage goalkeeper Predrag Rajkovic is the only potential debutant in Serbia's 23-man squad to play Colombia following his impressive performances at the European under-19 tournament in Lithuania this month.
Serbia have a slim chance of reaching next year's World Cup finals in Brazil. They are third in Europe's qualifying group A with seven points from as many games, nine behind Balkan rivals Croatia, whom they entertain on Sept. 6, and 12 adrift of leaders Belgium.