Sunday, November 24, 2013

Who Makes The Best PIZAA In Baseball?


Most of the readers of this blog have checked out the advanced fielding statistics at sites like FanGraphs and Baseball-Reference from time to time.  A metric such as Defensive Runs Saved (DRS) give us an idea of a player’s overall fielding performance.  It is given as runs saved above what would be expected from the average player at the given position.  It is discussed in more detail in the fielding glossary.

You may also have noticed two additional columns at FanGraphs labeled RZR and OOZ.  These are the Revised Zone Rating statistics developed by John Dewan, president of Baseball Info Solutions.  Dewan later developed the more detailed DRS metric.   The Revised Zone Rating system is comprised of the following measures:
  1. Balls in play within a fielder’s zone (BIZ)
  2. Plays made in the zone (Plays)
  3. Proportion of balls in zone converted into outs (RZR)
  4. Plays made outside the zone (OOZ)
A play is considered to be inside a positional zone if half the balls hit into that area are converted into outs by all the players in baseball at that position.  While the Revised Zone Rating system is less sophisticated than DRS, it is useful because it separates the plays a player made inside his zone from the plays outside his zone.  The data, of course, should be interpreted with caution as is the case with all defensive metrics especially with the increasing trend of defensive shifts.

Table 1 below shows how the distinction between in-zone and out-of-zone plays can be useful.  Phillies shortstop Jimmy Rollins converted 334 out of 407 (82.1%) of balls in his zone into outs in 2013.  Brewers shortstop Jean Segura had a similar number of balls hit into his zone (402) but had a smaller RZR (77.9%).  Conversely, Rollins made fewer out-of-zone plays (49) than Segura (98).  These data suggest that Rollins may have been the steadier fielder on balls hit in the shortstop zone but that Segura was better at making difficult plays.

Table 1: Revised Zone Rating Statistics for Jimmy Rollins and Jean Segura, 2013
Player
BIZ
Plays
RZR
OOZ
Jimmy Rollins 407 334 .821 49
Jean Segura 402 313 .779 98
 
Data source: FanGraphs.com  

Some readers may have wondered whether these statistics could be translated to runs above average like most of the other defensive metrics.  A few years ago, Colin Wyers (who has since been hired by 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 and I'm not going to repeat the whole process here.  If you want see all the math, you can read my post from last year.

Table 2 below shows the MLB leaders among shortstops in 2013.  The top shortstop in the majors was Andrelton Simmons of the Braves with 33 PMAA. The 33 plays made can be broken down into two parts: 30 Plays in Zone Above Average (PIZAA) and 3 Plays Out of Zone Above Average (OOZAA).  PIZAA and OOZAA may be two of the most amusing acronyms out there and you are probably relieved that I didn't show all the math.  Simply stated though, Simmons was exceptional on plays in the shortstop zone and slightly above average outside the zone.

The final column of the table shows that Simmons saving an estimated 25 runs for the Braves.  Simmons was also rated as spectacular by DRS (+41), Baseball-Reference's Total Zone (+30) and Baseball Prospectus' FRAA (+27).  

Former Tigers shortstop Jhonny Peralta had -2 PIZAA and -1 OOZA which shows that he was about average both inside and outside the zone.  This might be a surprising result, but if we look at two years of data (2013-2013), we see the Jhonny we know:  +14 in the zone and minus -21 outside the zone. 
Tigers current shortstop Jose Iglesias has unexpected number the last two years: +6 PIZAA and -1 OOZA but that's based on under 800 innings.  I would guess that his outside-the-zone play will rate much better in the future.
 
Table 2: Runs Saved by MLB Shortstops According to RZR, OOZ, 2013

Player
Team
Inn
RZR
OOZ
PIZ AA
OOZ AA
PMAA
RSAA
Andrelton Simmons
ATL
1,352
.876
73
30
3
33
25
Clint Barmes
PIT
804
.843
60
9
18
27
21
Pete Kozma
STL
1,051
.838
69
12
14
26
19
Jean Segura
MIL
1,251
.779
98
-10
33
23
17
Troy Tulowitzki
COL
1,029
.862
51
20
-3
17
13
Yunel Escobar
TBR
1,320
.782
90
-7
21
14
11
Pedro Florimon
MIN
1,099
.838
58
12
1
13
10
Alcides Escobar
KCR
1,388
.790
89
-4
17
12
9
Ian Desmond
WSN
1,400
.844
69
15
-4
11
9
Brendan Ryan
- -
854
.759
64
-12
19
8
6
Elvis Andrus
TEX
1,288
.822
63
6
-4
2
1
Zack Cozart
CIN
1,308
.849
54
15
-14
1
1
Alexei Ramirez
CHW
1,400
.820
65
7
-8
-1
-1
Starlin Castro
CHC
1,418
.804
72
0
-2
-2
-1
Brandon Crawford
SFG
1,226
.813
58
3
-6
-2
-2
Jhonny Peralta
DET
935
.796
48
-2
-1
-3
-2
Everth Cabrera
SDP
847
.804
41
0
-3
-3
-2
J.J. Hardy
BAL
1,417
.804
69
0
-5
-5
-3
Didi Gregorius
ARI
894
.795
43
-2
-4
-6
-4
Stephen Drew
BOS
1,093
.788
55
-4
-2
-6
-5
Adeiny Hechavarria
MIA
1,297
.801
61
-1
-7
-8
-6
Asdrubal Cabrera
CLE
1,099
.788
51
-4
-6
-10
-8
Jimmy Rollins
PHI
1,318
.821
49
7
-20
-13
-9
Omar Quintanilla
NYM
814
.771
33
-8
-9
-17
-13
Jed Lowrie
OAK
1,023
.758
43
-11
-10
-22
-16
Erick Aybar
LAA
1,203
.736
59
-21
-4
-25
-19
Data Source: FanGraphs.com

3 comments:

  1. Well we saw a lot of neat stuff from Iglesias with the glove last year, but we also saw quite a few mistakes and other miscellaneous stuff and he definitely has the capacity to get better from where he is now. We probably won't get too excited about his bat this year, so it's very important that they work hard to make sure he continues to develop and improve and really juice his defensive contributions to the team. I'm looking forward to seeing how he does with what will surely be his largest amount of time playing in a season yet. It should be quite fascinating to study and break down his defensive play all year long.

    ReplyDelete
  2. Speaking of which...how does Iggy compare on this list if we prorate him to 150 games at shortstop? And BTW, am looking forward to checking out your book, Lee.

    ReplyDelete
  3. If you take Iglesias' career numbers and extend to 150 games, he comes out to be about +9 RSAA. That's merging together very small sample sizes from different years though, so it's probably not too meaningful.

    ReplyDelete

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