Loose part in blower fan
 

I had my cabin air filter changed a couple months ago, and right after, the blower fan was making a terrible noise. I took the fan out and there was a leaf, but also this plastic part that I assume they knocked loose from somewhere when they changed the cabin filter. I couldn't see where it came from, so I took it out. Fan works great now, but I have no clue what this part is and if it's important or not. Can anyone tell me what this is and where it came from? Also, does it need to be put back somewhere?

Pics of the part below. 2012 RX.

Thanks!