CR10 V2 - O-rings found on print bed mid print??

Hi,

I allowed my CR-10 V2 to print over night. When I checked it in the morning, the printer was still operating but there was a clear decline in print quality.

On closer inspection, I noticed two 1.5cm o-rings on the print bed that were not there the night before.

I am trying to determine where these o-rings came from so I can replace them, and get my 3D printer working again.

Please see attached pictures.

Are these a part of the roller bearings that somehow came off during the printing process?

Thanks