Sean Green's New Groove

One of the stories out of Port St. Lucie is Sean Green's new sidearm delivery. He dropped down his arm angle late last season and apparently it is now even more pronounced. Here is Green's reasoning for making the change, per Adam Rubin:

Green said he has always struggled with repeating his delivery and as a result has had erratic control. He feels this angle helps him have a consistent release point, while also presenting an unfamiliar look for batters.

Green debuted the revamped delivery last September 8th, following a 1/3 IP, two hit, two walk outing vs. the Rockies a week earlier. Here are his peripheral stats from Opening Day through September 1st ("Stretch One") vs. September 8th through Closing Day ("Stretch Two"):

(Note: GB% = groundball percentage; SwStr% = swinging strike percentage. You know the rest.)

His ERA did improve from 5.15 to 1.50 between these stretches, but given BABIP and LOB% variance, especially in small samples like these, it's always best to look at defense independent pitching statistics. Pointing to the decrease in batting average of opposing hitters from .263 to .116 is not strong evidence that the change will increase effectiveness going forward. His peripherals worsened, except for GB%. Is a 75% groundball rate sustainable? Probably not, and it's impossible to draw any meaningful conclusions about the delivery tweak because of small sample size. So I won't. However, a look at some pitch f/x data can provide some insight about the differences between Stretch One and Stretch Two and what might be expected from Green.

Side note, before returning to Green: There's some really great pitch f/x work produced on a near-daily basis on the Internet. Sam examined a Jenrry Mejia AFL start back in October. This piece by Nick Steiner at THT in December was excellent. Harry Pavlidis of Cubs f/x, Beyond the Boxscore and also the upcoming Amazin' Avenue Annual is constantly producing worthwhile f/x content. Pitch f/x is a useful tool which will continue to enhance pitcher analysis, both inside and outside front offices. All that said, these types of pieces aren't for everyone and I can understand why. It has nothing to do with the quality of writing by the authors, and more to do with grasping the meaning of the data. I consider myself well-versed (but not all-knowing) in the latest sabermetric concepts but often have to look back at pitch f/x tutorials, like this one at BtB, to provide a refresher on exactly what horizontal and vertical movements, whiff rates, etc. signify. It's often not approachable for the casual fan. Sometimes you'd rather just check out the latest in AA MS Paint creation than read about Jon Niese's curveball location. Hopefully information presented here is accessible and the analysis makes sense. If there are any f/x savants out there, feel free to provide input and/or correct something written about Green.

All of the following data is courtesy of the pitch f/x resource, Texas Leaguers. First up, here is a comparison of Green's release point in Stretch One vs. Stretch Two:

(This is from the perspective of the batter. The box at the center of the graph is a rough strike zone.)

The change is noticeable, as the release point is about one-and-a-half feet lower and one foot farther outside. Rubin reported that Green's current release point is somewhere between Stretch Two and Chad Bradford's knuckle scraper, which you can see here.

Green's pitch selection changed from Stretch One to Stretch Two. He stopped throwing sinkers and stuck with the four-seam fastball, which he threw roughly 70% of the time. Although the Stretch Two four-seamer might also be labeled a kind of "sinker", based on the amount of pitch movement it produced. But I'll get to that in a bit. He increased curveball frequency and decreased slider and changeup frequency. Additionally, Green experienced about a 3.5 mph decrease in fastball velocity. This makes sense considering it's generally tougher to generate velocity as arm angle lowers from 3/4 delivery. As the character Doc Windgate said in Major League: Back To The Minors, (paraphrasing), "Decrease velocity, increase movement".

Next up is a comparison of those daunting pitch movement graphs:

There wasn't much change in breaking ball movement (the blue and green cluster on the right side of the graphs). There was, however, a sharp change in fastball movement (the red and purple cluster on the left side of the graphs). Green's fastballs sunk more in Stretch Two than Stretch One, by about five or six inches. There was also slightly less horizontal movement (tailing in to a right-handed batter), by about two or three inches. If the increase in sink will cause an improvement in Green's already impressive groundball and home run rates, then this experiment just might pay off. Strikeouts will likely decrease but the tradeoff could mean improved effectiveness, as long as it's coupled with a lower walk rate. Control has always been a bugaboo for Green, so hopefully the consistent release point he seeks via the new delivery will mean fewer walks.

Some quick takeaways:

• Sean Green lowered his delivery in September of last season. It is even lower at Spring Training.
• The lower delivery led to a decrease in velocity but also an increase in sinking action.
• Jerry Manuel thinks Green can be more than a righty specialist.
• Jerry Manuel is delusional. Feliciano vs. Diaz.
• Green was a useful major league reliever prior to changing his arm angle. He should still be useful, as long as he is deployed correctly and placed in situations where he can succeed.