Tuesday, August 5, 2008
Top MLB Defensive Players by Zone Rating through Aug 4, 2008
Since it's been a while since I described how the zone rating numbers I use here are calculated, here's a refresher for those who are new to the blog. This is all based on work previously done by Sean Smith and Chris Dial over at Baseball Think Factory.Zone Rating was introduced in 1987 by Stats Inc. as a way to measure defense. The idea behind it was to break up the field into zones of responsibility for each position. Any ball that is converted into an out at least 50% of the time by a typical defender in their defined zone is considered a fieldable chance. Balls that are out of zone but fielded get included as a chance as well.
ZR is a decimal from 0 to 1, and it's simply chances converted into outs divided by total chances. So if a player has 10 fieldable chances and converts 8 of them into outs, his zone rating would be .800. I pull my data from CNNSI's team pages, which shows the actual chance data as 'Ch'. I separate the AL and NL because there are systemic differences in the infield due to pitchers hitting, giving NL infielders easier chances. I roll up all the league data to get the average ZR at each position, and then the dorkiness begins.
Let's take sabermetric defensive whipping boy Derek Jeter through the calculations. This season, Jeter has 296 fieldable chances. His zone rating is .838, which means he has converted 248 of those chances into outs. The AL average ZR at SS this season is .828. We multiply that by Jeter's chances to get an average plays made, in this case that's 245. So Jeter has made 3 plays more than an average AL SS this season. We multiply those extra plays made by the average linear weights run value of a play not made at shortstop, which is 0.753 runs (0.27 for the out not recorded, 0.483 for the hit or error). That gives us 3 plays made above average times 0.753 = 2 runs saved.
Here are the run values for all the positions.
POS RV
1B 0.798
2B 0.754
3B 0.800
CF 0.842
LF 0.831
RF 0.843
SS 0.753
Plays not made in the OF are more damaging since they are more likely to be extra-base hits, but infielders see more chances in general. Here's the average distribution of chances for each position in the AL this season pro-rated over 162 games.
1B: 265
2B: 526
3B: 435
CF: 462
LF: 372
P: 174
RF: 367
SS: 523
To figure out the runs saved value pro-rated to 162 games, I just divide total RS by innings played and multiply by 1440 innings.
Zone rating isn't perfect, particularly in a single season. There are several limitations that can impact the numbers.
- Park factors are an issue, particularly in certain OF like Fenway and Coors
- ZR assumes that all chances are the same. A defender who plays behind a team that allows more hard-hit balls will look worse in zone rating than a similar defender who plays behind a better pitching staff.
- ZR zones are static and don't account for positioning. This has often been considered at least a partial explanation for Jeter's below average seasons.
Most of these factors even out over time, so multi-year zone rating is generally a decent approximation of a defender's ability.
So no, I don't think Jeter is a good defender because he's having a good year. I think he's a below average defender who's having a good year.
Since the question comes up sometimes, why do I use ZR instead of RZR (revised zone rating)? Revised zone rating was developed by John Dewan, who developed the original Stats ZR. So if it's revised, it has to be better, right? Not necessarily. RZR uses smaller zones and then breaks out plays made out of zone separately. In theory, this isn't a bad thing I guess, but it raises an issue. We don't know how many OOZ (out of zone) chances a player sees. So we have to estimate that using either in zone opportunities or some other way, and to me that raises more uncertainty into something that's already a difficult thing to assess. So I just don't use it for now, although I'm open to considering it if I stumble on a good way to handle OOZ chances.
I want to re-iterate again that this is Chris Dial's system, not mine. He did the heavy lifting to come up with this and I thank him for it, even though he's a Mets fan. So with that enthralling explanation out of the way, here are the top 50 defenders in the majors this season by accumulated year-to-date runs saved.
| Player | TM | LG | Pos | G | INN | Ch | ZR | PM | Avg ZR | AvgPM | Diff | RS | RS/162 |
| Ellis, Mark | Oak | AL | 2B | 99 | 879 | 296 | .889 | 263 | .824 | 244 | 19 | 14 | 24 |
| Crawford, Carl | TB | AL | LF | 104 | 890.2 | 246 | .915 | 225 | .847 | 208 | 17 | 14 | 22 |
| Gomez, Carlos | Min | AL | CF | 103 | 879.1 | 335 | .940 | 315 | .894 | 300 | 15 | 13 | 21 |
| Gutierrez, Franklin | Cle | AL | RF | 67 | 509.2 | 121 | .992 | 120 | .873 | 106 | 14 | 12 | 34 |
| Teixeira, Mark | Atl | NL | 1B | 102 | 898.2 | 189 | .947 | 179 | .871 | 165 | 14 | 12 | 18 |
| Rolen, Scott | Tor | AL | 3B | 84 | 735.2 | 208 | .865 | 180 | .800 | 166 | 14 | 11 | 21 |
| Utley, Chase | Phi | NL | 2B | 109 | 947 | 343 | .851 | 292 | .810 | 278 | 14 | 11 | 16 |
| Pujols, Albert | StL | NL | 1B | 96 | 815.2 | 173 | .948 | 164 | .871 | 151 | 13 | 11 | 19 |
| Jones, Chipper | Atl | NL | 3B | 82 | 702.2 | 199 | .844 | 168 | .779 | 155 | 13 | 10 | 21 |
| Beltre, Adrian | Sea | AL | 3B | 108 | 947.2 | 264 | .845 | 223 | .800 | 211 | 12 | 9 | 14 |
| Feliz, Pedro | Phi | NL | 3B | 97 | 770.1 | 238 | .828 | 197 | .779 | 185 | 12 | 9 | 18 |
| Kennedy, Adam | StL | NL | 2B | 67 | 507.2 | 195 | .872 | 170 | .810 | 158 | 12 | 9 | 26 |
| Hermida, Jeremy | Fla | NL | RF | 98 | 832.1 | 210 | .929 | 195 | .878 | 184 | 11 | 9 | 16 |
| Jones, Adam | Bal | AL | CF | 106 | 929 | 287 | .930 | 267 | .894 | 257 | 10 | 9 | 13 |
| Giles, Brian | SD | NL | RF | 97 | 869.10 | 207 | .923 | 191 | .878 | 182 | 9 | 8 | 13 |
| Vizquel, Omar | SF | NL | SS | 56 | 458.2 | 142 | .908 | 129 | .836 | 119 | 10 | 8 | 24 |
| Sizemore, Grady | Cle | AL | CF | 104 | 918 | 276 | .928 | 256 | .894 | 247 | 9 | 8 | 12 |
| Phillips, Brandon | Cin | NL | 2B | 109 | 960.1 | 338 | .840 | 284 | .810 | 274 | 10 | 8 | 12 |
| Guillen, Carlos | Det | AL | 3B | 75 | 632 | 218 | .844 | 184 | .800 | 174 | 10 | 8 | 17 |
| Cabrera, Orlando | CWS | AL | SS | 110 | 944.2 | 364 | .854 | 311 | .828 | 301 | 10 | 7 | 11 |
| Gerut, Jody | SD | NL | CF | 64 | 488.00 | 161 | .932 | 150 | .878 | 141 | 9 | 7 | 21 |
| Chavez, Endy | NYM | NL | RF | 49 | 375.2 | 107 | .953 | 102 | .878 | 94 | 8 | 7 | 26 |
| Anderson, Garret | LAA | AL | LF | 61 | 531.1 | 125 | .912 | 114 | .847 | 106 | 8 | 7 | 18 |
| Payton, Jay | Bal | AL | LF | 65 | 376.1 | 131 | .908 | 119 | .847 | 111 | 8 | 7 | 26 |
| Scott, Luke | Bal | AL | LF | 77 | 621.1 | 167 | .892 | 149 | .847 | 141 | 8 | 6 | 15 |
| Cabrera, Melky | NYY | AL | CF | 108 | 927.2 | 277 | .921 | 255 | .894 | 248 | 7 | 6 | 10 |
| Sweeney, Ryan | Oak | AL | RF | 49 | 289.2 | 80 | .963 | 77 | .873 | 70 | 7 | 6 | 30 |
| Beltran, Carlos | NYM | NL | CF | 107 | 952.2 | 312 | .901 | 281 | .878 | 274 | 7 | 6 | 9 |
| DeWitt, Blake | LA | NL | 3B | 84 | 690 | 240 | .808 | 194 | .779 | 187 | 7 | 6 | 12 |
| Berkman, Lance | Hou | NL | 1B | 103 | 893 | 216 | .903 | 195 | .871 | 188 | 7 | 6 | 9 |
| Overbay, Lyle | Tor | AL | 1B | 108 | 939.2 | 232 | .892 | 207 | .863 | 200 | 7 | 5 | 8 |
| Pierre, Juan | LA | NL | LF | 72 | 597 | 127 | .913 | 116 | .863 | 110 | 6 | 5 | 13 |
| Barton, Daric | Oak | AL | 1B | 87 | 726.2 | 121 | .917 | 111 | .863 | 104 | 7 | 5 | 10 |
| Rollins, Jimmy | Phi | NL | SS | 82 | 719.1 | 249 | .863 | 215 | .836 | 208 | 7 | 5 | 10 |
| Aybar, Erick | LAA | AL | SS | 67 | 554.2 | 214 | .860 | 184 | .828 | 177 | 7 | 5 | 13 |
| Inge, Brandon | Det | AL | 3B | 32 | 191 | 62 | .903 | 56 | .800 | 50 | 6 | 5 | 38 |
| Figgins, Chone | LAA | AL | 3B | 68 | 598 | 142 | .845 | 120 | .800 | 114 | 6 | 5 | 12 |
| Howard, Ryan | Phi | NL | 1B | 109 | 954 | 173 | .908 | 157 | .871 | 151 | 6 | 5 | 8 |
| Rios, Alex | Tor | AL | RF | 59 | 517 | 118 | .924 | 109 | .873 | 103 | 6 | 5 | 14 |
| Burrell, Pat | Phi | NL | LF | 108 | 835 | 168 | .899 | 151 | .863 | 145 | 6 | 5 | 9 |
| Ross, Cody | Fla | NL | CF | 76 | 618 | 205 | .907 | 186 | .878 | 180 | 6 | 5 | 12 |
| Victorino, Shane | Phi | NL | CF | 91 | 774.1 | 221 | .905 | 200 | .878 | 194 | 6 | 5 | 9 |
| Nix, Jayson | Col | NL | 2B | 20 | 143.1 | 61 | .918 | 56 | .810 | 49 | 7 | 5 | 50 |
| Fontenot, Mike | ChC | NL | 2B | 59 | 358.2 | 113 | .867 | 98 | .810 | 92 | 6 | 5 | 20 |
| Lewis, Fred | SF | NL | LF | 91 | 730.2 | 151 | .901 | 136 | .863 | 130 | 6 | 5 | 9 |
| Youkilis, Kevin | Bos | AL | 1B | 91 | 760 | 130 | .908 | 118 | .863 | 112 | 6 | 5 | 9 |
| Izturis, Maicer | LAA | AL | SS | 50 | 431 | 146 | .870 | 127 | .828 | 121 | 6 | 5 | 16 |
| Kearns, Austin | Was | NL | RF | 68 | 591 | 167 | .910 | 152 | .878 | 147 | 5 | 5 | 11 |
| Glaus, Troy | StL | NL | 3B | 106 | 911 | 269 | .799 | 215 | .779 | 209 | 6 | 4 | 7 |
| Joyce, Matt | Det | AL | LF | 28 | 197 | 48 | .958 | 46 | .847 | 41 | 5 | 4 | 33 |
TM: Team
LG: League
Pos: Position
G: Games
INN: Defensive Innings at Position
Ch: Playable Chances
ZR: Zone Rating (PM/Ch)
PM: Plays Made
Avg ZR: ZR by average defender at the same position and in the same league
AvgPM: Estimated Plays Made over the same # of chances by an average defender
Diff: Difference between PM and AvgPM
RS: Runs Saved
RS/162: Runs Saved pro-rated to 162 games
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