What you are looking at is not a pokeball at all, it's (as darth said) an itemball. While item balls sometimes contain pokeballs, they usually just have a random item such as a super potion. Itemballs are shown as pokeballs to catch the players eye, do that they see sine thing familiar and interact with it to see what it is. So, when you pick it up, you will not gain a pokeball, unless a pokeball was inside of the itemball, otherwise you will obtain a different item. The only exception to this is when the itemball is actually a voltorb/foongus or their evolutions.