Morocco's back-up goalkeeper at the Africa Cup of Nations, Issam Badda, has been diagnosed with a 'benign' form of malaria, says the team doctor.
Badda received a blood transfusion at a hospital in Gabon's capital Libreville before his release on Wednesday.
Doctor Hefti Abderrazak says Badda is recovering at the team hotel and is receiving treatment for Type 3 malaria.
"He will take oral medicine for three days and I hope he can resume activity on Thursday," said Abderrazak.
"We're in a region where the malaria is among the most serious in Africa. It can affect the brain, so thankfully Badda was on preventative treatment."
Marouane Chamakh is also recovering after picking up a stomach illness.
The Arsenal forward sat out training on Wednesday, after which the team doctor was forced to deny reports that Chamakh had anything more sinister.
"I can confirm that Chamakh does not have malaria," Abderrazak stressed. "All his tests are fine and he should be okay to resume training with his team-mates on Thursday."
Oussama Assaidi, Michael Basser and Mehdi Benatia also sat out training on Wednesday due to minor injuries.
Chamakh, Assaidi, Basser and Benatia all featured in Morocco's surprise 2-1 loss to Tunisia in Libreville on Monday.
That result makes the game against co-hosts Gabon, who beat Niger 2-0 in their opening match, a must-win for the Atlas Lions.
Abderrazak added the Moroccan players were taking malaria medication for their trip to the tournament in the central African country.
Neighbour Equatorial Guinea is also co-hosting the finals, which started on Saturday and end on 12 February.