[lollipopcurve]

The TINSTAAP thing is based on the fact that pitchers can have catastrophic injuries. Pretty simple idea. Of course, given that this applies to most all minor league pitchers, you can simply ignore it. I'd also say there are more variables that go into the development of a major league ready starter than go into the development of an everyday position player. Beyond health, there's the development of fastball command and the development of secondary stuff. Then the finer points -- pitch efficiency, working out of jams, holding runners. Basically -- there's more to pitching than there is to hitting.

I like Stephenson's chances -- a lot. But he is not a shoo-in ace at this point, IMO. Those guys are rare and take years to develop, including years at the major league level for almost all of them.