The Changchun Yatai star was on target as the Super Eagles walloped the Indomitable Lions 4-0 in the first leg but was replaced in the second half by Kelechi Iheanacho.
And the coach insisted he will wait until the very last minute before deciding on whether his talisman should play in Monday’s encounter.
“If Ighalo cannot play, we will decide at the last moment,” Rohr told media.
“We have two possibilities; we have Kelechi [Iheanacho] and we have Anthony [Nwakaeme]. So we have two centre forwards who are ready to play for him.
“I will like to use the same but there is a little question about Ighalo and his leg, so we can’t afford to take any risk.
“The possibility is to bring players but that will be decided [on Tuesday morning].”
The German tactician also disclosed that his men are prepared to withstand whatever the Indomitable Lions throw at them.
“We expect a big beginning of the game against Cameroon who will try a lot of aggressiveness to play,” he continued.
“This is a physical team but we are ready physically also to have a big fight with them.”
A win for the Super Eagles at Stade Ahmadou-Ahidjo, Yaounde will hand a ticket to 2018 Fifa World Cup Russia with two games to spare.