On the one hand, if this list of Mark Prior's historical comps at Minor League Ball doesn't alarm Cubs fans, nothing will. On the other hand, that's the way it works with the early career of any great starter, isn't it? If PECOTA and Bill James had been around when Steve Carlton was breaking in, his comps would have been all these other guys who burned out.

This isn't to say there's nothing to worry about, but it is to say that historical comparisons, when made fairly, are bound to be pessimistic, simply by the nature of the game: there are vastly more burnouts and failed careers in the annals than there are Hall of Famers.