We've had one as president (Zachary Taylor) and there's at least one in the HoF (Wheat, although he spelled it Zack), so why set limitations? I know those are old examples, but the name did make a comeback and was in the top 20 for most popular baby names every year from 1992-2003. I'm sure we will see more of them, as pitchers, middle infielders, slugging first basemen (which is what I always thought it sounded like), and eventually as ushers and hot dog vendors.