The 25-year old Argentine playmaker is struggling with a hamstring injury and will have to go through a fitness test on Friday before he is declared fit for the season decider with the Brisbane Roar at Suncorp Stadium.
Mariners coach Graham Arnold said that he would take no risks with Perez ahead of the biggest game of the season.
“If Patricio doesn't get through the fitness test he won't play,'' Arnold declared.
"We'll be taking no risks. Hopefully he pulls up okay but if he doesn't I'm confident in the players we've got.''
Arnold said that young gun Mustafa Amini and vice-captain John Hutchinson would be Perez’s likely replacements.
"Musty is having a ball this season and Hutch has plenty of big game experience. We've got options,” he added.