Mixing Fantasy & Reality: More on Velocity and Miguel Diaz

The New Standard Velocity

Fantasy owners are going to need to understand how velocities are now being reported. MLB Advanced Media is now reporting only StatCast collected velocities, not Pitchf/x. These StatCast values are calibrated five feet closer to the pitcher than the old values and therefore will be a small bit faster. All broadcasts and I am pretty sure all stadium values will use these new higher values as well. The big question is that with almost 10 years of Pitchf/x information already collected, what adjustment needs to be made?

Dave Cameron noticed that reported velocities were up 1 mph. I went and dug a bit further and with the help of Jared Cross (Steamer’s creator), we came up with the increase closer to 0.77 mph. This morning MLB.com’s Tom Tango released an explanation and had the difference in the same range depending on initial pitch speed.

One problem issue with a +/- change, the harder a person throws, the greater the difference. Slow curves have a 0.6 mph difference but 100 mph fastballs are at 1.0 mph. Now, Tom did provide this chart:

Note: This chart and value have been updated because of reasons explained in this thread.

 

The percentage change ranges from 99.2% to 99.4%. These percentages seem to be more consistent across all velocities. So from now on when I report fastball velocities, I will adjust previous values (’16 and earlier) to the new values using this formula:

Reported Velocity = Old Velocity/.993

Now, some other changes are in the works with pitch break amounts being corrected so this article is probably not the last time StatCast information will be examined.

 

Velocity Changes to Kendall Graveman to Ideal Velocity:Groundball Rate Mix

With the new velocity adjustments, here are some pitchers who have seen significant velocity changes (full list). First, here are four starters who showed significant velocity loss.

Note: The velocities in the image aren’t corrected, so the drop is more than shown and the increases are less.

Jake Arrieta (-3.4 mph)

Rick Porcello (-1.5 mph)

Noah Syndergaard (-1.9 mph)

Danny Duffy (-3.5 mph – closing, -1.7 mph – starting)

I am not going to worry about these four just yet but I would like to see them trend up in their next start or two. Now for some good news, here are four guys with velocity increases.

CC Sabathia (+2.6)

Madison Bumgarner (+1.9)

Adam Wainwright (+1.5)

Kendall Graveman (+2.4)

The other Jeff has already written about Graveman twice since his Opening Day start. One issue with Graveman’s velocity increase is that his sinker won’t have time to sink and will generate fewer ground balls. For reference, here are Graveman’s game groundball rates plotted against his velocity (’16 and ’17).

As Graveman has thrown harder, his groundball rate has dropped. A pitcher should try to keep their pitches in the flyball zone (GB% < 30%) or groundball zone (GB% > 55%) and out the area in between area where line drives are common. Here are his overall fastball velocities and GB% over the past three seasons:

Kendall Graveman’s Sinker Velocity and Groundball Rate
Year GB% Velo (corrected)
2015 58.6% 91.5
2016 52.7% 93.5
2017 ??? 94.5

The drop in GB% was seen from ’15 to ’16 with a 6% drop from a 2 mph fastball increase. The important factor to ponder is if the velocity gains will override the groundball rate drop. It’s time for a little study.

First, I converted velocity to a swinging strike rate. Using corrected velocities, I found the average swinging strike rate at certain fastball speeds:

Now with a velocity projected swinging strike rate, we can then give a pitch an ERA grade using this formula:

pERA = (5.20 – 12*(SwStr% * 2 – 8%)) * (-3.518*GB%^2+2.344*GB%+.629)
pERA=(5.2-12*(2*(0.006573*FBv-0.5365)-8%))*(-3.518 * GB%^2 + 2.344*GB% +0.629)

With this formula, I created a reference table for a projected ERA knowing the pitch’s velocity and groundball tendencies.

Fastball pERA Given Velocity and Groundball Rate
20% 25% 30% 35% 40% 45% 50% 55% 60% 65% 70% 75% 80%
85 5.58 5.80 5.92 5.93 5.85 5.66 5.37 4.98 4.48 3.88 3.18 2.38 1.47
86 5.43 5.64 5.76 5.77 5.69 5.51 5.22 4.84 4.36 3.78 3.10 2.31 1.43
87 5.28 5.48 5.60 5.61 5.53 5.35 5.08 4.71 4.24 3.67 3.01 2.25 1.39
88 5.12 5.33 5.44 5.45 5.37 5.20 4.93 4.57 4.12 3.57 2.92 2.19 1.35
89 4.97 5.17 5.28 5.29 5.22 5.05 4.79 4.44 4.00 3.46 2.84 2.12 1.31
90 4.82 5.01 5.12 5.13 5.06 4.89 4.64 4.30 3.87 3.36 2.75 2.06 1.27
91 4.67 4.86 4.96 4.97 4.90 4.74 4.50 4.17 3.75 3.25 2.66 1.99 1.23
92 4.52 4.70 4.80 4.81 4.74 4.59 4.35 4.03 3.63 3.15 2.58 1.93 1.19
93 4.37 4.54 4.64 4.65 4.58 4.43 4.21 3.90 3.51 3.04 2.49 1.86 1.15
94 4.22 4.39 4.48 4.49 4.42 4.28 4.06 3.76 3.39 2.94 2.41 1.80 1.11
95 4.07 4.23 4.32 4.33 4.27 4.13 3.92 3.63 3.27 2.83 2.32 1.73 1.07
96 3.92 4.07 4.16 4.17 4.11 3.97 3.77 3.49 3.15 2.73 2.23 1.67 1.03
97 3.77 3.91 4.00 4.01 3.95 3.82 3.63 3.36 3.02 2.62 2.15 1.61 0.99
98 3.61 3.76 3.84 3.85 3.79 3.67 3.48 3.22 2.90 2.52 2.06 1.54 0.95
99 3.46 3.60 3.67 3.69 3.63 3.52 3.33 3.09 2.78 2.41 1.98 1.48 0.91
100 3.31 3.44 3.51 3.52 3.47 3.36 3.19 2.96 2.66 2.31 1.89 1.41 0.87

From 2015 to 2016, Graveman’s sinker pERA went from a 3.66 pERA to 3.80 pERA with the velocity bump. Assume his velocity stays at 94.5 mph and his GB% drops to 50%, his fastball pERA stays at 3.80. If the assumptions hold true, his fastball will be just as effective as it was last season as he moves from great groundball numbers to OK rates.

 

Quick looks: Miguel Diaz

This tweet got me intrigued to further examine this Rule 5 pick of the Padres.

Such a nasty fastball. I decided to take it a step further and watch his one inning appearance.

Fastball: 95-98 mph with late glove side bite.

Change: 87-88 mph with late drop.

Curve/Slider (labeled slider by ~18 mph less than fastball): 82-83 mph with 2-7 motion. It didn’t seem to fool hitters so he may be tipping the pitch.

I like his potential and it will be interesting to see how the Padres eventually utilize him. In this game, he was used in relief with the Padres way behind. If he continues to throw like this, he could quickly move up to a better relief role.

 

Video

Ronald Torreyes jumped onto my radar last season when my computer projection system like him more than scouts. It’s obvious why scout dismissed him, he’s maybe 5’6. But he did hit this home run yesterday.

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Jeff, one of the authors of the fantasy baseball guide,The Process, writes for RotoGraphs, The Hardball Times, Rotowire, Baseball America, and BaseballHQ. He has been nominated for two SABR Analytics Research Award for Contemporary Analysis and won it in 2013 in tandem with Bill Petti. He has won three FSWA Awards including on for his MASH series. In his first two seasons in Tout Wars, he's won the H2H league and mixed auction league. Follow him on Twitter @jeffwzimmerman.

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Ryan Brock
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This is a stupid, stupid move by the statcast folks to change point of measurement for velocity. Now any time I see a velo reading this year, I’ll have to ask whether that’s “corrected” as you’re suggesting here, or not. I really doubt that everyone is able to scramble together a consensus decision on this, given that they waited to announce this change until after the season had already started.