The former Manchester City forward last scored for the three-time African Champions in November 2017 and his form at club level has also not been impressive, having extended his goal drought to six months with Leicester. Also, he has not started a game for the side since mid-December.
Hence, the German tactician has shown his displeasure with the commitment of the player.
"I think he must be more professional," Rohr told media before Friday's win over Seychelles.
"We're not satisfied with his performances the last time he was with us.
"There's a new coach at Leicester City (Brendan Rodgers) and it (his omission) will be an opportunity for Iheanacho to show during this international window that he wants to get back into the starting team of Leicester.
"Personally, I think it's a good thing for him to stay back at his club to prove this.
"It's not good enough to be funny all the time. You must show that you are serious by working hard every day in the training sessions.
“And show that you seriously want to come back into the team at the club and also with us."
Nigeria defeated Seychelles 3-1 on Friday at the Stephen Keshi Stadium to seal the top spot in Group E with 13 points from six games.
They will take on Egypt on Tuesday as part of their preparation for the African Cup of Nations scheduled for June.