Touching BasesNovember 26, 2010
The Decade in Basic Fielding: Adjustments
By Jeremy Greenhouse

Last week, I looked at the decade's leaders in plays made per ball in play. Now, I'll take a look at the context in which they played.

This might not qualify as basic anymore, given the intensive amount of computation time that goes into these adjustments, but I do find them intuitive. I attempted to replicate the "without" part of Tom Tango's "With or Without You" system by finding how many plays the average fielder would have made given a specific fielder's set of circumstances. That entails deciding on a situation to control for, finding how often a fielder was in that situation, and calculating the rate of plays other fielders made in that situation. For example, third basemen are twice as likely to record an out on a ball in play if the batter is right-handed as opposed to left-handed. Therefore, if Eric Chavez faced right-handed batters 60% of the time this decade, while the league normally faces 58%, then we would need to take away a couple dozen plays made by Chavez to adjust for his advantage.

Below, I present the chart for batter handedness adjustments. The adjustment figure is the number of plays you would need to add to or subtract from each fielder's plays made due to context. The adjusted rate incorporates that adjustment.


A batter handedness adjustment doesn't make much of a difference for catchers, pitchers, or center fielders, but for players in the corners, it can be huge.

Last week, I found that Freddy Sanchez had the lowest rate of plays made at 2b, and Jack Wilson the highest at SS, and here we see that the Pirates must have faced a ridiculous number of RHBs.

The number of left-handed hitters the Yankees roll out could impact the numbers, as Nomar Garciaparra and Bill Mueller earn large adjustments, while Manny Ramirez comes out even worse than before.

Feel free to click on the links below to see similar charts to the one above.

Pitcher Handedness Adjustment

Pitcher handedness adjustments correlate with batter handedness adjustments. It seems to me, however, that batter handedness adjustments are way more useful in measuring fielding.

Those are easy to calculate and to comprehend. he next several are trickier. Calculating park adjustments when some players play every single day limits the "without" part of the sample. Here, take a look.

Ballpark Adjustment

Let's use, you guessed it, Derek Jeter and the Yankees as our starting point. Both Yankee stadiums have seemingly played exceedingly difficult for shortstops. Shortstops make plays in the Bronx on under 11% of balls in play, and the average is 12%. You might be thinking that Jeter drags down the average, but remember, I controlled for this by finding the rate of plays made when he wasn't on the field. You might also be thinking that the Yankees wide array of left-handed hitters drag down the average. That, I didn't account for. So it's tough to say what can be attributed to the ballpark. Maybe the grass is shorter or greener or something. Or maybe the Yankees play with poor fielding shortstops and hit with players who don't hit to that side of the field. The same could be said for Jimmy Rollins, who has dominated the shortstop position for the Phillies over the last decade, and his own lineup is also dominated by left-handed hitters. I think it would be too hard and probably not worthwhile to try to determine ballpark adjustments for infielders.

The conclusion that I think can be drawn from these ballpark adjustments is that Coors Field kills outfielders.

Pitcher Adjustment

I think there's some good stuff in there.

Jimmy Rollins and Orlando Cabrera have played in front of stingy pitchers, whereas Miguel Tejada and Rafael Furcal have benefited from pitcher generosity. Chipper Jones as both a left fielder and third baseman moves close to average when you control for the pitchers he's had to deal with.

Batter Adjustment

Rollins, playing behind pitchers who were unfriendly, fielded in front of hitters who helped him out a fair deal.

These next two will be heavily biased, but I thought they might be interesting.

First Baseman Adjustment
Center Field Adjustment

There are a lot of conflating factors here, as first basemen and center fielders might play every day with their teammates, killing the "without" sample, and they share a ballpark every day, bringing in other effects.

Anyway, I wasn't surprised to see that Chase Utley and Jimmy Rollins might have made more plays with a different first baseman.

With center fielders, I was looking for evidence of ball-hogging, but don't think I found any.

Batted Ball Adjustment

This is the only time I'm not using the entire 2000-2009 dataset, as a significant portion of balls were not classified. Most, if not all, unclassified balls went for hits, so the adjusted rates are all higher than the league average rates.

Three of the top five pitcher adjustments go to guys who played for the Braves, which means they generated a lot of ground balls. This results in the Joneses getting underappreciated as outfielders, especially Andruw, who I showed last week was one of the best at catching balls in the air, and now we see that he had hundreds of fewer opportunities than he would have playing for another team.

The information used here was obtained free of charge from and is copyrighted by Retrosheet. Interested parties may contact Retrosheet at 20 Sunset Rd., Newark, DE 19711.


That chart is really confusing. You ordered it by Adjustment, which means that the viewer can't tell who the new leaders and trailers are, since it's not ordered by Adjusted Rate. Can you run a copy of that chart which is sorted by Adjusted Rate so we can all see who the new leaders/trailers are?

When you make the adjustments, do you include the player himself in the calculations for context? For example, when you adjust for pitchers and you estimate how many plays Chipper should have made, are you using stats for Maddux, Glavine, and Smoltz that include their pitching with Chipper playing behind them? If so, that will create a problem for players like Chippper who played a long time with a few pitchers. (He'd look much better because he's being compared to a weak fielder -- himself.)

Sabes, I could do that, but I wanted to focus on the adjustments more than the players for this.

Guy, I am not using stats for Maddux, Glavine, and Smoltz that include their pitching with Chipper playing behind them. I tried to replicate WOWY as best I could. Sorry if I didn't make that clear.

I'm not as sure as you are that Chipper as a weak fielder. I seem to recall Chris Dial making an argument in favor of Jones' defense on this site.

You may be right. I meant only that if a fielder who made few plays was included in the pitchers' stats, then that player would be held to a lower standard.

However, WOWY has Chipper at -261 plays at 3B through 2008. Not sure how to reconcile that with your data: