Al Medlej was due to stand against Sheikh Salman Bin Ebrahim Al Khalifa of Bahrain, Yousuf Al Serkal of the United Arab Emirates and Thai Worawi Makudi in Thursday's vote in Kuala Lumpur.
The Saudi said in a statement in Arabic on Wednesday that he was a compromise candidate and only planned to stand if the other two West Asian candidates stepped down from the race.
But Sheikh Salman and Al Serkal have ramped up their campaigns over the last few weeks in a battle that has turned tetchy, leaving Al Medlej to follow through with his pledge.
What happens now to the support he has garnered will be the cause for much discussion in the Kuala Lumpur hotel which was bristling with delegates ahead of the vote on Thursday morning.
Both Al Serkal and Sheikh Salman have said they are favourite to take the majority of votes from the 47 member associations and succeed disgraced Qatari Mohamed Bin Hammam, who was banned for life by FIFA in 2011, as the next president of the body.
Worawi's campaign appears to have stuttered with the vote expected to be two-horse race between the two West Asia candidates which has opened schisms within the 13-member region.
Last month, Al Medlej talked about working as an AFC vice-president in a television interview if Al Serkal won the vote.