The problem with most of the handwringing by people over rushing a pitcher too quickly is that is hard to define. What is “too quickly”? Are we judging based on some sort of age/level curve where they should be? Are we basing it on years of professional experience? Are we basing it on performance? I feel most people who have that mindset claim it’s based on performance. Moving a kid up before he has shown mastery of a given level. But isn’t that in and of itself a selection bias? I mean if you think kids who didn’t dominate a given level are moved too soon, are you just poo-pooing the kids who were never going to dominate that level in the first place because of their inherent lower level of ability?

The concept is too nebulous and unsupported by objective data to worry about it at this point.

I suspect the common refrain is simply selection bias. People look in hindsight for reasons why their former favorite top prospect didn’t pan out. Guess what, lots of pitching prospects don’t pan out. Trying to peg it on a player being rushed is relatively unlikely at least in the grand scheme of things. If there is any effect at all, it is likely small in magnitude.

And that a statement such as: “Turner was hurt by the organization’s over-aggressive development plan in an effort to compensate for a weak minor league system,” is poor journalism. It’s not stating that it could possibly have slowed his development, it’s stating a theory as fact, one that can’t be supported by anything other than opinion.