Mazda 3 Serpentine belt TENSIONER has play and rattle
 

Recently had the serpentine belt changed. Now noticing some play in the tensioner. It also makes an irregular clicking sound. Also, when I touch it there is a bit of movement going on inside of it. Not sure if the bearings are going bad? Does it need immediate replacement? How challenging is this to do at home for someone that only does oil changes? Here's a video: https://goo.gl/photos/BJB1e2guZTGjh3L78