All this [Parts 1, 2 and 3] has been leading up to what I had been meaning to write about Dominic Leone (Talk40 #25), in response to a comment from "part-time" (which is now more than a week old):

• The one thing I remember most when Leone was drafted is Tim Chalberg's comment 'Dominic Leone, RHP, Clemson - Some scout must see a potential adjustment that could make Leone a better fit in pro ball than college. I don't see much in the numbers that excites me. Grade: F'. Prospect Insider now ranks him as the number 19 prospect in the Mariners as of mid-season. No one else even has him on the radar, as near as I can tell, but from what the numbers are saying, the small money spent on the kid as a bonus was well spent. Bang for the buck, it would appear the Mariners own the scout who suggested the kid a big thank you.

A "Grade F" draft pick!

And ... Doc invited me to not be so "understated."  So how's this:

• In January, the "Spectometer" ranked Leone as having the third-best "stuff" in the organization, after only Carter Capps and Stephen Pryor. 
• In March, I ranked Leone #25 in the Spec66, and said: "if Leone really has become virtually unhittable, why end up on the wrong side of history?"

***

So here's the story so far.  Leone was pretty much an ordinary college pitcher.  A starter. 

Late in his college career, he decided he needed a boost and became infatuated with Mariano Rivera's cutter.

He started teaching it to himself by watching videos on YouTube.  Yes, that's the story.  YouTube!

The same ACC scouts who brought us Kyle Seager, Brad Miller and Danny Hultzen apparently thought they saw something worth pursuing.

So he came to Everett last year as that "Grade F" draft pick, and pitched 33.0 innings.

He gave up 17 singles, 3 doubles, 0 triples, 0 homers.

BA-against .174.  SLG-against .204.  ISO-against .030.

He walked a bunch, but ... no one could hit the ball against him.  No one got "good wood" on the ball.  Period.

***

Now ... 2013.

Are we allowed to throw out April?  In this case, maybe, since Leone is ordinary if he doesn't have his "nuclear pitch," and maybe he didn't quite have it in April.

But looking at May onward:

BA-against .184. SLG-against .229.  ISO-against .044.

Same story.  No one can hit.  No one connect with the ball.  No one gets "good wood."

He's faced 343 pro batters and given up 14 extra-base hits.  And six of those were in April.

That's a 4.1 XBH%.  You know who's career rate is 4.4%?  Yep.  Mariano Rivera.  [Felix is at 6.1%.]

***

But a huge difference in 2013: the walk rate has been falling like a rock.

• 2012 5.2 BB/9.
• April 4.1 BB/9.
• May 2.9 BB/9.
• June 0.8 BB/9.
• July 0.0 BB/9.

It seems like he's now developed the confidence to throw strikes and know he's not going to get hit.  And that brings his value up considerably.

***

So ... can we conclude that Leone has developed a "nuclear pitch"?

Well ... we know:

• Before he started throwing it, hitters got very "conventional" results.  He was nothing special.
• Now that he throws it, batters get very few hits, and virtually no extra-base hits.
• Now that he throws it consistently for strikes, he is virtually unstoppable.

The evidence seems pretty strong that something verrrrrrry interesting is going on.

Does that mean that Leone is set for a Mo Rivera career?  No.  But he seems to have a better chance than most.  And that can't be a bad thing.