It depends on how important Ajax take the game, next week I am assuming an Ajax victory in the addendum. If PSV then doesn't win on Saturday, Ajax will be the champions if I'm not mistaken. Should this happen, will Ajax still take Sunday's game seriously? Should PSV win, they will try to secure the championship title in the home Stadion. But Ajax has the more important game tomorrow I think.
Maybe not mathematically yet but Ajax are already the champions if we think realistically. They are going to play their missing game against Utrecht next week and they will most probably beat their opponent.
I am very sure that Ajax will not play seriously in the match against AZ, one of the factors is that AZ has played 29 matches, but Ajax has only played 28 games. Besides that too, Ajax definitely wants to keep the performance of its players to stay fit.
Besides that, PSV might be having a hard time facing their opponents before entering the month of May. Many PSV Players Have Injuries.
If Ajax don't play very seriously then AZ's chance for a win will be quite high. It will be more dependent on the result of the Ajax-Utrecht game. If Ajax win that, they may not take the AZ game very seriously.