Peralta Lacks Range But Protects His Territory

Most of the readers of this blog have checked out the fielding statistics at FanGraphs from time to time.  Statistics such as Ultimate Zone Rating (UZR) and Plus/Minus or Defensive Runs Saved (DRS) give us an idea of a player’s overall fielding performance.  They are given as runs saved above what would be expected from the average player at the given position.  They are 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 UZR and 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,

Table 1 below shows how the distinction between in-zone and out-of-zone plays can be useful.  Tigers shortstop Johnny Peralta converted 262 out of 307 (85.3%) of balls in his zone into outs in 2012.  Mariners shortstop Brendan Ryan had a similar number of balls hit into his zone (309) but had a smaller RZR (81.6%).  Conversely, Peralta made fewer out-of-zone plays (49) than Escobar (87).

These data suggest that Peralta may have been the steadier fielder on balls hit in the shortstop zone but that Ryan was better at making difficult plays.  Some of this could have been due to positioning prior to plays, but I think most observers of the Tigers would agree that it makes sense that Peralta would be a lot better at in-zone players than out-of-zone plays.   

Table 1: Revised Zone Rating Statistics for Jhonny Peralta and Brendan Ryan, 2012

Player	BIZ	Plays	RZR	OOZ
Jhonny Peralta	307	262	.853	49
Brendan Ryan	309	252	.816	87

 Data source: FanGraphs.com  

Table 2 presents some zone rating statisics for Tigers who played regularly throughout the year.  Among 21 MLB shortstops with roughly 100 or more games worth of innings, Peralta ranked second in revised zone rating behind Ian Desmond (.855) of the Nationals.  Peralta was 17th in baseball in number of out-of-zone plays.  Orioles shortstop J.J. Hardy led the majors with 109 out-of-zone plays.

It might surprise some that first basemen Prince Fielder ranked fairly high on both categories finishing in the top third of MLB in both RZR (5th) and OOZ (6th).  He led the majors in innings played and would have dropped a couple of notches if we looked at something like OOZ per inning, but these numbers still make him look better than some of his awkward errors would suggest.

Other Tigers rankings were not too shocking with second baseman Omar Infante and center fielder Austin Jackson getting good ratings across the board.  It's possible that Infante accumulated a lot of his good statistics with Florida though as he stumbled at times with the Tigers.  On the downside, third baseman Miguel Cabrera was near the bottom in both RZR and OOZ. 

Table 2: Revised Zone Rating Statistics for Detroit Tigers Regulars, 2012

Pos	Name	Inn.	RZR	Rank	OOZ	Rank
1B	Prince Fielder	1,393	.823	5/20	27	6/20
2B	Omar Infante	1,246	.836	3/22	49	8/22
SS	Jhonny Peralta	1,278	.853	2/21	49	17/21
3B	Miguel Cabrera	1,322	.682	14/16	29	13/16
CF	Austin Jackson	1,184	.939	6/21	95	3/21

Data source: FanGraphs.com