Jim Callis' new mock draft for MLB.com has the Pirates taking California high school shortstop Jacob Gatewood at No. 24:
This is probably on the low end for Gatewood, who gets mentioned as high as No. 7 and could go in the teens to Kansas City or Washington. Pittsburgh could go for another toolsy prepster in Harrison or an advanced college bat such as Gillaspie, Reed or Fisher.
MLB.com ranks Gatewood the No. 22 prospect in the draft. He isn't very likely to stick at shortstop (particularly given his big frame) and may wind up at third base (given his strong arm). Scouts also have questions about his ability to hit advanced pitching. He has a long swing, and may have trouble with strikeouts. His power, however, is very highly regarded, and he has great bat speed. He's committed to USC.
Callis only projects through the end of Comp Round A at No. 34, so he hasn't projected anyone for the Pirates' new pick at No. 39.