Nats' Starting Pitchers: Are They Doing it Right?

Effective, durable major league starters account for the vast majority of a major league team's innings pitched throughout a season. It's no surprise, then, than teams preach certain tactics to starters concerning their approach to hitters. Spacious ballpark? Don't be afraid to pitch up. Thin air? Keep the ball down. Facing a white-hot hitter? Tread carefully (whatever that means).

Gameplans are used at the strategic level, too. The Nationals are the perfect example of that: In July 2012, Nats pitching coach Steve McCatty compared the strikeout to a product of a certain animal's rear end. Instead, McCatty prefers efficiency, usually achieved through weak contact. Despite several reasonable views to the contrary, this approach persisted through the 2013 season.

One subset of pitching to contact is pitching to earn ground balls, since ground balls have the lowest run value among batted balls. So, it was somewhat tough to argue when several Nats starters stated their desire to get worm burners last season. Yet the team's three best pitchers in 2013 -- in no particular order, Stephen Strasburg, Jordan Zimmermann, and Gio Gonzalez -- all have strikeout stuff, and throw high velocity fastballs.  Was the grounder focus a good idea, then?

Fastball Spin Rates

I looked at fastball spin rates to determine whether Strasburg, Zimmermann, and Gio's hard stuff was effective at generating ground balls. Why fastballs? Because this offering was the pitch most frequently used across major league baseball, and by each of the three hurlers.

So we've got the pitch we're going to isolate. How to measure the pitch's ability to get ground balls?

Several quality articles after the 2013 season reviewed technology (developed by a company called Trackman Baseball) which captures the spin rate of pitches. Let's get right to the point.  Zach Day, a former major league pitcher and current employee of Trackman, wrote that:

[a]n average MLB fastball makes 2200 revolutions per minute (RPMs) on its way to home plate . . .

What’s a good fastball spin? As evidenced by the chart below, the spin put on a fastball directly correlates to ground ball rate, fly ball rate, and swings-and-misses. (As for whether high or low spin on a fastball is better—that’s a topic for a different day.) Knowing your spin helps you better understand what type of pitcher you are at present.

Fastball Spin MLB 2010-2013
RPM (00s)	SwStr%	GB %
<- 20	5.5%	47.3%
20 - 21	6.1%	43.0%
21 - 22	6.8%	40.3%
22 - 23	7.7%	38.7%
23 - 24	8.7%	37.4%
24 - 25	10.4%	36.3%
25 ->	13.4%	37.2%

We've all heard about "sneaky" and "heavy" fastballs, and this data illuminates how we can translate these terms into hard data. "Sneaky" fastballs have high spin rates, allowing them to "jump" on the batter through late rise (or more precisely, late failure to drop). These heaters generate, as the chart quoted above shows, higher swing and miss rates than low spin fastballs. "Heavy" fastballs, as Day explains, have lower spin rates, causing the ball to sink more.  This characteristic helps induce ground balls.

Let's explain the "why" of rise and fall here. Remember the Magus Effect? Probably not. I don't know anyone who didn't skip that section in last year's pre-season stat tome. Anyway, here's the quick and dirty from the PDB on it, with the ball spinning backwards as viewed from the pitcher's perspective looking to the catcher:

Faster air = lower pressure = upward movement due to higher pressure air below the baseball. Basically, the greater the backspin, the greater the lift. Yeah, science!

So: if Stras, ZNN, and Gio throw heaters the most, and they focus on ground balls, do their fastballs demonstrate favorable ground ball spin rates?

First, a couple of qualifiers on what we're looking at in this piece. Obviously, there's more than one way to assess whether a certain strategy is ideal or not -- here's some more unmerited self-aggrandizement from last pre-season on game theory -- and it's clear that ground balls are not the ideal result in every case. Nor are the pitchers we look at below exclusively fastball twirlers; part of their talent lies in their ability to throw multiple pitches for strikes.

Recognizing these (and other) limitations, it's time to see what we've got.

Stephen Strasburg

Multiple writers reported that Strasburg was going to focus on ground balls this past season; here's Jerry Crasnick of ESPN.com:

Strasburg's 44.2 percent ground ball ratio last year (according to FanGraphs) was middle-of-the-pack, but he's going to try to elevate that by mixing in more two-seamers this year. If his 10 ground ball outs against Miami were any indication, he's on the right track.

Right. Here are Strasburg's data points, with the MLB average in the right hand column for perspective. "FB" is four seam fastball:

Strasburg goes to his fastball more often than the average major league starter, and also generates more ground balls with the pitch he uses most often. However, his whiffs/swing rate with the 95-MPH heater is a little over 2% less than other big league starters.

And then there's the spin rate: fifty revolutions less than the MLB average, which is meaningful enough.

If you buy into Day's use of the terms above, Strasburg is working with a fairly "heavy" offering, perhaps even more so when you consider he's getting 5% more ground balls than the Trackman's average (40%) listed above. His four seam spins less than the major league average, which appears to be a favorable thing for his focus, all else being equal.

Interestingly, Strasburg's two-seam fastball (per Texas Leaguers; Brooks has it as a sinker) has a spin rate of 2,400, but his whiff rate on the pitch is only 11.4%. We'll see some more interesting data like this, and it's important to keep in mind that -- like most things in baseball -- there's very little to be certain of.

Jordan Zimmermann

Zimmermann told reporters earlier this year that he will work for ground ball outs. Patrick summed this approach up aptly after ZNN's one-hit shutout against the Reds in April:

• Zimmermann On Getting Groundouts via MASN "Just throw it down and away and let them beat it into the ground and let [Ian Desmond] and [Danny Espinosa] do what they do all year."

Based on his spin fastball spin rate, was this a good idea? Yes.

Zimmermann's fastball spin is relatively glacial compared to the major league average. And his results support Trackman's research. His ground ball rate on the pitch is approaching 50%, and his whiffs are below the mean; just what you'd expect. Zimmermann is even exceeding the average ground ball rate for heater spin rates under 2,000 (47.3%).

Gio Gonzalez

Although it is not exactly an outright affirmation of a grounder-centric approach, Gonzalez told Patrick last year that he has "always been a big fan of pitching to contact... You want to stay out there as long as possible, keep your team in the game and try to give your bullpen a chance to rest up and actually use them when you really need to use them."

Gonzalez really relies on his sinker to get ground balls, and he uses it about 8% less often than his four seam. As the chart below indicates, the pitch he throws most often isn't necessarily the best for following the grounder approach.  And for a guy who uses his sinker in tandem with his fastball, that's okay.

We see that Gio works with a lower ground ball rate on fastballs than his starting pitcher peers, but also has a higher whiff/swing rate. Why? Of the three starters, Gio sports the highest fastball spin rate. This feature generates plenty of rise, hop, jump, sneak, or whatever the jargon is that the kids are using, which correlates with swinging strike rates better than raw fastball velocity.

We saw some contrary information with Stephen Strasburg's sinker, and Gio shares some of the same curiosities. His sinker -- TexasLeaguers appears to label it a two-seam -- generates a ton of ground balls (49.7% rate), but spins to the tune of 2,400 RPM.  It also does not generate many whiffs (13.7%).

In sum, Gio can reach back with the fastball when he needs a swing and miss, and audible to a sinker if a grounder is preferable.

Conclusions

Spin rates are not everything. If you believe that it's a good thing for Strasburg, Zimmermann, and Gio to have pitch qualities that work in favor of their pitching coach's general approach on the pitches they throw most often,** then there's something positive to take away here. And regardless whether you believe that pitching to contact is bunk -- certainly reasonable -- the most important thing is that the Nationals are pushing this pitching style, like it or not.

At worst, then, it seems to be making the best of a bad situation. At best, it is evidence of a team blending hard information with scouting (appreciating defensive quality, acknowledging that efficiency is best for their pitchers) through coaching instruction to formulate a general strategy that plays to their pitchers' abilities. My guess is that the needle is slightly more towards the latter.

Add Doug Fister, Ross Detwiler, and Tanner Roark into the mix and you've got all worms within a 10 mile radius of South Capitol Street on alert. With the exception of Detwiler, all sport below-average fastball spin rates.

In conclusion, and with the caveats mentioned above, the Nats' 2013 horses seem to be maximizing their ability to achieve favorable results.

**Although Gio's spin rate data doesn't suggest his fastball and sinker are best for grounders, I think there may be something wonky on lefty readings, considering Det's sky high spin rate (and high ground ball rates). So, I thought he can fit.