Providing Context to StatCast Power Numbers

May 1, 2018

Last week, I wrote about the expected power from JaCoby Jones and Lewis Brinson. In the article, I mentioned the hitter’s rank compared to other hitters with no context resides just the rank. Today, I correct this flaw in my analysis by finding the league averages and putting the data on the 20-80 scouting scale.

While overall ranks do provide some information, it’s tough to put the rankings into context. Nelson Cruz is first in average exit velocity (EV) at 97 mph. Dropping down 2 mph in exit velocity is Luke Maile at #10. Two more is Jacoby Jones at #26. And another two is Francisco Lindor at #75. The first 4 mph in drop was just 26 players while the next 2 mph was 49 players. The batted ball decline rate is not linear and just a few tenths of a mile-per-hour can jump a player 20 spots in the rankings.

I need a way to label hitters and had to invoke some math. I took the hitters with 100 batted balls per season from 2015 to 2017 and found the overall average value. Using the 20-80 scouting scale, I gave the average values a 50-grade.

Next, I found the standard deviation from this average in both directions. For each standard deviation from the mean, I changed the grade by 10 points (standard procedure behind the scouting scale).

In some instances, a value went negative. In those cases, I fudged the number a bit (actual values in parenthesis).

I tired of writing about during math. Here are the final values in which I assumed most people just skipped to. They are in order from the StatCast leaderboard available at Baseball Savant.

StatCast Batted Ball Placed on a 20-80 Scale

Grade	Range	Max EV	Avg EV	FB/LD EV	GB EV	Max Dist	Avg Dist	Avg HR Dist	% > 95 mph	Brls/PA
80	+3 SD	120	95	100	94	498	233	434	58%	11%
70	+2 SD	117	93	97	91	476	213	422	50%	9%
60	+1 SD	113	90	95	87	454	192	409	42%	6%
50	Average	110	87	92	84	432	171	397	34%	4%
40	-1 SD	107	85	89	81	409	151	385	26%	2%
30	-2 SD	103	82	87	78	387	130	373	18%	1% (-1%)
20	-3 SD	100	79	84	75	365	109	360	10%	0 (-3%)

So going back to Jones and Brinson, here are their StatCast power grades.

JaCoby Jones’s 2018 StatCast Grades

Stat	Value	Grade
Max EV	112	60
Avg EV	93	70
Max Distance	422	45
Avg Dist	194	60
Barrel %	6.8%	60
Average	–	59

Lewis Brinson’s 2018 StatCast Grades

Stat	Value	Grade
Max EV	114	60
Avg EV	87	50
Max Distance	429	50
Avg Dist	144	35
Barrel %	3.8%	50
Average	–	49

From these numbers, Brinson has shown a bit more raw power this season. On the other hand, Jones has been much more consistent with his approach with an overall above average power profile.

The values can be used help find above and below average power hitters. For example, I took the five categories from above and then found the hitters with below average traits in each. One name immediately stuck out from this season, Brian Dozier (2017 stats included).

Brian Dozier’s 2017 & 2018 StatCast Grades

Stat	2018 Value	2018 Grade	2017 Value	2017 Grade
Max EV	104	30	112	60
Avg EV	86	45	88	50
Max Distance	384	30	435	50
Avg Dist	155	40	190	60
Barrel %	1.7%	40	5.7%	60
Average		37		56

His power has dropped from above average to well below average. The big key for me is the max value drops. He just doesn’t seem to have much raw power in his swing right now. His preseason training could have taken a back seat when he was dealing with a kidney stone. Or he could be hiding a semi-major injury. He is definately off.

Hopefully, I could add some context to the StatCast batted ball data. Owners can now have a better idea of a player’s value than just his rank among other hitters. Comparisons and trends can be found more easily.

BAL	CHW	LAA
BOS	CLE	OAK
NYY	DET	SEA
TBR	KCR	TEX
TOR	MIN	HOU

ATL	CHC*	ARI
MIA	CIN	COL
WSN	MIL	LAD
NYM*	PIT	SDP*
PHI	STL	SFG