The Post-Gazette has a good feature on UCLA pitcher Gerrit Cole, one of the top prospects in June's amateur baseball draft, that doubles as a good explanation of the potential differences between Cole and fellow top prospect and Rice third baseman Anthony Rendon. The Pirates have the first pick of the draft, so they get their choice of one or the other; Rendon and Cole are widely regarded as the best two prospects in that draft, usually in that order.
Baseball America editor Jim Callis consistently has ranked Rendon first, though he recently acknowledged that "Cole is making a push" at No. 2. ESPN's Keith Law has it the other way, calling comparisons between Cole and Strasburg "reasonable" and writing two weeks ago that "there is absolutely no question" Cole is No. 1.
The Pirates are not commenting on any specifics of their No. 1 pick, but they are known to be focusing heavily on these two, while still not ruling out others. There is internal concern about Rendon's physical stature and health, and there is concern about Cole simply because he is a pitcher.
Ultimately, the decision will come down to which player the Pirates like best, but the differences between the types of players Rendon and Cole are do matter - a lot. The Pirates have tons of good pitching prospects in the minors, but relatively few good hitters. Rendon would help remedy that. And, much more importantly (since the Pirates won't be picking for need with the first overall selection in the draft), pitching prospects, even college prospects, are very dangerous commodities - they often get hurt or lose velocity or bite on their pitchers. Rendon, as the article points out, has had plenty of injuries himself, however.