Leicester City and Nigeria striker Kelechi Iheanacho has not scored a goal since September
The 22-year-old was overlooked for the Super Eagles’ two matches this month after failing to score a goal for club or country since September.
Rohr was scathing of Iheanacho on the eve of his team’s Nations Cup qualifier against Seychelles.
“I think he must be more professional,” the German coach said.
“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.”
Rohr was asked by reporters whether he expected more from a Nigeria international.
“It’s not good enough to be funny all the time,” he responded.
“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.”
Iheanacho made an immediate impact to the start of his senior international career, scoring seven goals in 11 matches.
But a combination of a loss of form and lack of confidence have left him searching for his first international goal since scoring against Argentina in November 2017.
Iheanacho has 10 goals in 58 matches for Leicester City since joining the former Premier League champions from Manchester City in August 2017.
At international level, he has scored eight goals in 24 appearances for Nigeria since making his senior debut against Swaziland in November 2015.
He starred as Nigeria won the 2013 Under-17 World Cup in the United Arab Emirates for a record fourth-time and emerged as the tournament’s outstanding player, being voted the Most Valuable Player.
He scored six goals to secure the Silver Boot as the competition’s second-highest goal-scorer.