I just got this ball off of ebay, so it was never drilled for me. As you probably saw from the pics, it has one of the interchangeable thumb units installed. I'm not sure if it's a Switch-Grip or a Vise-IT, but I will find out early this evening. It's hard for me to gauge the span without the inner sleeve installed in the thumb, but I'm thinking it's fairly close to the high 4s or right at 5". My plan was to take it to my shop tonight to see if he can drill me an inner sleeve; that way I could throw it to see what I think without having to do any plugging. I'd have a better idea of the span at that point. Were you interested in buying or trading?