Pitching by the Numbers: Nelson an off-speed ace

Let’s look at 2015 MLB play-by-play data to assess which pitchers have the best off-speed pitches according to the hitters — meaning they swing and miss at them the most.

I firmly believe that it’s the fastball that’s the foundation for all successful pitching. If you can’t evade hard contact with that pitch you cannot get ahead of hitters and set up these secondary offerings. But once you have the count in your favor, and especially with two strikes, you need to finish hitters with pitches that wrinkle.

So this is a 2015 skills analysis. I have a high confidence level that these numbers are bettable, however injury always looms for hurlers and that’s typically going to impact these pitches the most.

Let’s start with the curveball. I had a scout tell me at length years ago that the curve was a dying pitch because the break is so large that umps do not call it a strike nearly as often as they should. Major league pitchers who feature it have verified that this is still true, even with our advanced pitch technology and umpire grading. So the swing-and-miss rate for this pitch is probably more important than for the others. Hitters have to be fooled into thinking the curve is a fastball and get that bat off their shoulder.

All of these stats are current as of Wednesday, May 13.

Nelson clearly has an out pitch. My numbers are generally down on him. But this is a big plus and suggests that he may be closer to dominance than his current stats indicate (8.0 Ks and 3.0 BBs/9).

Unfortunately, I don’t have the data for last year at the moment so I can’t tell you what Kershaw’s rate of missed swings on curves was last year. But it seems unlikely that this is the reason for this disappointing start. Note that he’s throwing the pitch only about 15 percent of the time and featuring his slider about twice as often.

Strop has closer stuff when you combine his curve with his 95 mph fastball. The good thing about curveballs is that they show the lowest platoon splits.

Shields’ increase in strikeout rate seems explained by how he’s now featuring his curve, at the expense of his once lethal changeup.

Alright, let's move on to the slider:

I wrote in the Wall Street Journal on Thursday about how ridiculous Miller and Betances are not just currently but historically.

But there’s Nelson again. His fastball must stink, right? No, Fangraphs says his curve is the pitch that’s hurting him. But obviously it’s a quality pitch. He clearly is hanging it too much. Nelson is one of the game’s biggest mysteries to me now. How can you top the list in two breaking pitches and throw 93 mph and not be really good?

I have to change my opinion on Gray not just in light of this slider data but also because of the results his last three starts. When you rack up three straight, nine-plus-K outings, you can no longer be knocked for not being able to put hitters away.

Heston is a surprise and has been a buy of mine on Twitter @michaelsaslfino for most of this season. Well, not even a buy since he was just sitting there on waivers until his last outing (10 Ks, 0 BBs). This shows Heston not only has a great sinker but also a put-away pitch.

Richards is a great pitcher and I’d go all-in on him being my mixed-league ace.

Finally, a look at the changeup artists:

I believe the changeup is the most important pitch in baseball. I always liked Ramirez because of it. But I can’t go there in mixed league. I’d buy in deep AL-only formats but that’s really saying nothing because everyone with a pulse goes in those formats. Perhaps Ramirez throws the change so much (35 percent) that it’s not changing off of anything.

Martinez just does not look athletic to me out there. Something seems off. Pedro Martinez noted this too recently about Carlos and I agree. Pedro thinks Carlos’s mechanics are so terrible that he belongs in the bullpen.

Liriano is on two lists, with Nelson. He’s leading starters in allowing just 5.3 hits per nine innings and now you know why.