Morocco's Marouane Chamakh is hoping to be fit to face Gabon in Libreville.
The Arsenal striker has been hit by food poisoning but expects to recover for a game Morocco must not lose if they are to make the quarter-finals.
There are also doubts over Oussama Assaidi, with an Achilles tendon injury, and Michael Chretien Basser, who has an ankle problem.
Gabon defender Moise Brou Apanga should be fit after missing the 2-0 win against Niger with a muscle injury.
Morocco need to win or at least salvage a point to stay in contention for a place in the quarter-finals after losing their opening game against rivals Tunisia.
But Belgian coach Eric Gerets has confidence in a side that boasts some top-quality players.
"The quality of the squad doesn't change overnight," he said. "If I didn't know this group for more than a year then maybe I would be asking myself questions but it wouldn't be logical to start doubting my players now.
"Of course I want to see how they react mentally in front of a crowd that will be behind our opponents, but the signs I have seen in training have given me great hope."
Gabon coach Gernot Rohr is approaching the game cautiously despite the high expectation of the home fans.
"Of course it's a big test because it's a big team," he said. "Morocco have wonderful players who play in big championships.
"We don't have that but we have confidence now and I think my team has a very big motivation to win this game even against the big players."
The Panthers coasted through their opening 2-0 win over Niger, with St Etienne forward Pierre-Emerick Aubameyang particularly impressive.