Small Engines (Lawn Mowers, etc.): ball bearing in air filter, ball bearing in air filter, carburetor

Question
I was doing the normal tune-up routine on my John Deere L130. When I took the air filter off I found a 1/4" ball bearing inside the filter. I have changed the filter several times before and have never seen this.  Where does it belong?  

Answer
I'm going to bet it came out of the carburetor.  The factory has to drill holes into the body of the carb and they use bearings to plug the holes.  There have been a few cases where these bearings came loose and the result was a blown engine. 1/4" sounds pretty big for this though. Is it really that big?  Thanks, PK.