BA's Jim Callis: Feliz, Perez No. 1 starters?

Baseball America's Jim Callis hosted a chat today and was asked which pitchers on the publication's top 100 prospect list have "true No. 1 potential." Part of Callis' answer:

I'm stingy when it comes to anointing prospects as potential No. 1 starters. I want to see one dynamic pitch, at least one plus pitch to go with plus command and plus makeup—and even then I err on the side of caution. That's why there are only six pitchers whom I would stamp as having legitimate No. 1 starter potential: Stephen Strasburg (No. 2), Brian Matusz (No. 5), Neftali Feliz (No. 9), Martin Perez (No. 17), Tyler Matzek (No. 23) and Jacob Turner (No. 26).

That really says something about the Rangers' farm system to have two of the six he mentioned. BTW, the numbers beside the players are where they are ranked in the Baseball America top 100.