Who’s got the best fastball on the Giants?

Yes, I’m back on my Statcast b-s. This time, let’s take a look at the best fastballs on the Giants. MLB’s Statcast data tells us the effective spin rates of each pitch thrown by a pitcher in 2018 and has several years of data to give us the general “average” of each pitch type.

So let’s look at baseball’s most common pitch: the four-seam fastball. It’s the pitch that moves pitchers through a farm system and helps hitters get to the major leagues. It’s an important pitch, so let’s see who’s best on the Giants at throwing it.

First, you’ll need to know that the average MLB four-seam fastball is 92.9 mph and has a spin rate of 2,226 rpm (revolutions per minute). Next, you’ll need to know that “on fastballs, [...] high spin tends to lead to swinging strikes and fly balls, while low spin gets grounders.”

With all that in mind, here are the Giants’ results:

The “below average” fastball spin rates got red boxed. You’ll notice Madison Bumgarner there because the one four-seam fastball the Statcast computers recorded had an extremely low spin rate. But like I said last week, the four-seam fastball is not a part of his arsenal (Statcast combines two-seamers and sinkers), and there’s only 1 data point for the record, so we can safely ignore it.

Andrew Suarez has thrown the most four-seamers this season (51.2% of the time) and his spin rate is second to last on the team and far below the league average. That’s sub-optimal if you’re attempting strikeouts, but as we know, Suarez is much more of a groundball pitcher (53.5% rate against an MLB average of 48.5%).

Will Smith throws his four-seamer 44.9% of the time, so that’s another sub-optimal spin rate. Coupled with a 42% ground ball rate (alos below league average), it’s safe to say he’s gotten a little bit lucky. Dereck Rodriguez’s is also below league average, but unlike Suarez, he has a ground ball rate near 41% and a fastball velocity that’s also below the major league average, so it’s even easier to see that he’s been lucky.

Still, it’s not all about spin rate. That’s what I’m getting at here. As you can see, lower spin rate helps with ground balls, but we haven’t even gotten to velocity yet. I think when most of us consider best fastballs, we think of those that get swings and misses, and you’re more likely to get swings and misses with velocity and spin. So, in order to see whose best based on that, let’s take a look at whiff rates (swing and miss rates) for the top 5 fastball spinners we see up above.

Let’s remove Valdez and Melancon from the survey, though, since their fastball instances are fewer than 100. That leaves us with a top 5 of:

Ray Black - 97.9 mph / 38.1% Whiff Rate

Jeff Samardzija - 91.7 mph / 21.0% Whiff Rate

Reyes Moronta - 96.8 mph / 24.1% Whiff Rate

Chris Stratton - 91.1 mph / 18.3% Whiff Rate

Hunter Strickland - 95.1 mph / 18.1% Whiff Rate

Okay, so, the answer was right in front of us all along: Ray Black has the best fastball on the team.

Now! Now... maybe you think swings and misses don’t necessarily suggest overall effectiveness. Well, let’s do one more quick look at this top five but filtered through Statcast’s xwOBA (quick definition here) — what sort of outcomes did the computers predict based on the available pitch data?

Ray Black - 0.283

Jeff Samardzija - 0.327

Reyes Moronta - 0.315

Chris Stratton - 0.370

Hunter Strickland - 0.392

Here’s the scale for wOBA, which is the same for xwOBA:

.400 = Excellent
.370 = Great
.340 = Above Average
.320 = Average
.310 = Below Average
.300 = Poor
.290 = Awful

That, uh, that once again proves that when it comes to fastballs, Ray Black is where it’s at.