Friday, November 06, 2015

Anthony Gose Ranked Well On Lesser Known Defensive Measure

Tigers center fielder Anthony Gose ranked high on Revised Zone Rating Runs Saved statistic
(Photo credit: David Richard, USA Today Sports)

Knowledgeable Detroit Tigers fans who watched the team on a daily basis saw speedy outfielder Anthony Gose covering the vast center field of Comerica Park and considered him an asset to the team defensively.  So, they were perplexed by advanced metrics such as Ultimate Zone Rating (UZR) and Defensive Runs Saved (DRS) which suggested that he cost the Tigers 10-12 runs compared to an average center fielder.  There was however another statistic which was more in line with the observations of fans.

You might have noticed that Gose made 101 Out of Zone plays (OOZ) according to Baseball Information Solutions. This is good for fourth best among major league center fielders.  He did not rank nearly as well on the complementary statistic - Revised Zone Rating (RZR).  He had an RZR of .906 which means that he made 90.6% of the plays in his zone.  That placed him in the bottom third of center fielders.  The two measures together suggest that he had very good range, but was not as reliable turning more routine plays into outs.

There is a common misconception that RZR and OOZ are connected to either DRS and UZR, but they are not.  Whereas DRS and UZR break each position into several zones and treat each sub-zone differently, RZR and OOZ only have one zone for each position.

Some fans have asked whether RZR and OOZ can be translated into runs like the more complex defensive measures.  A few years ago, Statistics Analyst Colin Wyers (who now does his work for the Houston Astros) developed an algorithm which combined RZR and OOZ and translated these numbers into plays made above average (PMAA) and runs saved above average (RSAA). 

Wyers' algorithm has a lot of steps.  If you don't want to see all the math, you can jump to the table at the bottom of the post and look at the PMAA and RSAA columns.  Anyway,  Gose had the following numbers in 2015:

Innings = 1,120
Balls in Zone (BIZ) =  277
In Zone Plays = 251 
RZR = .906
OOZ = 101

First calculate the average RZR for center fielders (proportion of all plays in the zone successfully converted to outs) and consider that to be the expected RZR (EXPRZR) for each player.  From that, calculate the plays made in zone above/below the league average (PIZAA) for each player:

          PIZAA  = In Zone Plays - BIZ*EXPRZR

The average RZR for MLB center fielders in 2015 was about .914.  So, Gose's PIZAA = 251 -  277 x .914 = -2.  Thus, he made an estimated 2 plays in the zone below what would expect from an average center fielder.  

Next, assume that the number of balls hit outside the zone is correlated with the number of innings (a big assumption, but the best we can do given the available data). Then calculate OOZ per inning for all players combined at each position (EXPORATIO).  Compute, for each player, the plays made outside the zone above/below the MLB average (OOZAA):

          OOZAA = Out of Zone Plays - Innings*EXPORATIO

The EXPORATIO for center fielders in 2015 was .069.  So, Gose's OOZA was 101 - 1,120 x .069 = 24.  This means that he made an estimated 24 plays outside the zone above what you would expect from an average center fielder.  

Next, combine plays made inside the zone and plays made outside the zone to get plays made above average (PMAA):

           PMAA = PIZAA + OOZAA

Gose's PMAA was -2 + 24 =22.  So, he made an estimated 22 more plays than would be expected by an average center fielder.  

Some time ago, analyst Chris Dial (now a member of the Board of Directors for the Society for American Baseball Research - aka SABR) estimated that the average play made by a center fielder saves .842 runs.  So, we can estimate the runs saved/cost (RSAA) by  a center fielder as:

          RSAA = .842*PMAA

For Gose, that comes out to RSAA=19.  Thus, he saved the Tigers an estimated 19 runs defensively compared to an average centerfielder.  That is a lot better that the -10 and -12 he netted on UZR and DRS respectively.  

Table 1 below shows the statistics for all MLB center fielders with 900 or more innings in 2015.  You can see that Gose ranked fourth in baseball on RSAA.  The MLB leader was Royals fly catcher Lorenzo Cain (35) followed by Kevin Pillar of the Blue Jays (34).

Is RSAA any better than UZR or DRS or other advanced defensive metrics.  Probably not, but it has the advantage of dividing plays into inside the zone and outside the zone, which is information we don't get from other metrics.  As always, take these numbers with a grain of salt.  It is always preferable to look at multiple metrics and years when dealing with defensive data.  

In this case, the numbers on Gose are all over the place, so this might be one of those times where you need to make a judgement based on your own observation or the observation of others whose scouting instincts you trust.  

Table 1 Center fielder Runs Saved Leaders, 2015
Player
Team
Inn
RZR
OOZ
PIZ AA
OOZ AA
PMAA
RSAA
Lorenzo Cain
KCR
1,173
.942
114
8
34
42
35
Kevin Pillar
TOR
1,236
.954
113
12
28
41
34
Kevin Kiermaier
TBR
1,174
.928
100
5
19
24
20
Anthony Gose
DET
1,120
.906
101
-2
24
22
19
Odubel Herrera
PHI
1,065
.930
90
4
17
21
18
Mookie Betts
BOS
1,157
.935
93
5
14
19
16
A.J. Pollock
ARI
1,303
.924
104
3
15
17
15
Michael Taylor
WSN
802
.948
66
6
11
17
14
Juan Lagares
NYM
999
.916
81
1
13
13
11
Billy Hamilton
CIN
975
.949
69
8
2
10
8
Mike Trout
LAA
1,362
.933
96
7
3
9
8
Michael Bourn
- - -
858
.929
65
3
6
9
8
Carlos Gomez
- - -
959
.910
68
-1
2
1
1
Cameron Maybin
ATL
1,129
.867
90
-13
13
-0
-0
Jacoby Ellsbury
NYY
948
.925
60
2
-5
-3
-3
Austin Jackson
- - -
939
.895
65
-4
1
-4
-3
Dexter Fowler
CHC
1,324
.925
80
3
-11
-8
-7
Adam Jones
BAL
1,168
.918
71
1
-9
-8
-7
Joc Pederson
LAD
1,223
.929
72
3
-12
-9
-7
Charlie Blackmon
COL
1,209
.879
83
-9
0
-9
-7
Adam Eaton
CHW
1,280
.917
77
1
-11
-10
-8
Marcell Ozuna
MIA
924
.891
58
-5
-5
-10
-8
Billy Burns
OAK
1,066
.933
56
5
-17
-12
-10
Angel Pagan
SFG
1,061
.889
50
-6
-23
-29
-24
Andrew McCutchen
PIT
1,374
.913
50
-0
-44
-45
-38
Data source: FanGraphs.com

3 comments:

  1. I haven't seen a lot of scouting info on Anthony in the last year. Any idea what they had to say about his 2015 season?

    ReplyDelete
  2. Wow, I'm honored that Yoda reads my blog! I don't think I have any more access to scouts than you do, but I'll see Microline says about Gose's defense. For what it's worth, he gets high scores for his range on the Fan Scouting Report, but not so high for his hands .

    ReplyDelete
  3. Seems the young guys with talent like Iggy and Gose are keen to show off on hard plays but lack the consistent fundamentals to turn the routine plays.
    Call me Suzy, but isn't that the kind of thing a coaching staff is supposed to spot and work on with players?

    ReplyDelete

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