02 Altima Serpentine Belt

The serpentine belt on my 2002 Nissan Altima seems to have some play in it. I don’t notice anything in neutral or in park but when it is in gear and at a stand still, i can hear and see a large amount of play in the belt. My mechanic can’t get to it until next week. Any thoughts on what could be causing this? Thanks in advance. P.S. I am not a mechanic but have replaced just about everything on my old truck. This however is not my old truck.

The tensioner pulley has likely lost the ability to stretch the belt tight or it has seized where it won’t work correctly.

Your belt may be two years old or more and it has stretched.