It's subtle but it's there. Have a closer look at each of these two versions of the 1989 Topps Gary Sheffield rookie card. The version on the left is the everyday version we see everywhere. The version on the right is the exceedingly rare version.
Left: This is the version that, if you were to buy a brick of copies of this card, most, if not all of them would look like this. It's the close shot with Gary's chin closer to the "B" in Brewers. In this version, the top of his hat doesn't touch the Future Star text in the header. Additionally, less of his neck chain is visible.
Right: This is the version you almost never see. Or maybe you've seen it many times and didn't realize it, which is completely understandable. In this version, Gary's chin is higher up in the photo and the top of his hat touches the "e" in Future Star, which is placed higher up on the card. Somewhat more of his neck chain is visible here too. Overall, the cropping of the photo is just a little further up. There's also a flat white line along the bottom border. In some instances where subtle variations are found between two copies of the same card, the uncommon variation is often found exclusively in factory sets. This would support the notion that the uncommon version is less often found as a single.
1989 Topps Baseball is a set with a variety of interesting variations. The 1989 Topps Gary Sheffield fits in nicely with dialogue around errors and variations. I only discovered the existence of this variation a couple years back, at which point I had already put in over 25 years of collecting experience. Upon discovery, it actually took me a while to find the rare version of this card to go with my several copies of the common variety. I finally stumbled across one in a $1 bin at a show. I never, under any circumstance, thought I'd ever spend as much as $1 on a 1989 Topps Gary Sheffield rookie card but given that this was a variation of particular interest, it made sense. It was either that or a can of cola at the soda machine. I figured this was a much better investment than a frivolous commodity.