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Introducing the PART System to Defensive Runs Saved

December 18, 2019
Defensive Runs Saved has received its biggest update since the release of The Fielding Bible: Volume IV in 2015. For infielders, the Range and Positioning System has been replaced with the PART System, which stands for Positioning, Air balls, Range, and Throwing.

This new system offers the ability to split infielder performance on groundballs and short line drives into three different components going back to 2013. We already had the ability to evaluate players on air balls, but the other three components of PART offer a brand new look at players.


Positioning Runs Saved is actually removed from a player’s overall DRS total because more often than not the coaching staff is handling positioning. Here are the players at each position who benefited or were hurt most from positioning.

Positioning Runs Saved Leaders and Trailers, 2019
Pos Leader(s) Trailer(s)
1B 5 - Brandon Belt -4 - Eric Hosmer, Matt Olson
2B 17 - Yolmer Sanchez -4 - Daniel Descalso
SS 22 - Willy Adames -5 - A. Rosario, X. Bogaerts, D. Swanson
3B 7 - Eugenio Suarez -13 - Matt Chapman
Because they’re moved around before almost every single play, middle infielders have a lot of room to save runs with positioning. That Willy Adames and Yolmer Sanchez saved as many runs as they did is a compliment to their coaching staffs but also an indication that their previous Range and Positioning Runs Saved totals (10 and 5 respectively) overstated their performance.

Also, Matt Chapman’s incredibly low Runs Saved total is indicative of his ability to sacrifice positioning because he can make the throw on plays down the line. More on Chapman in a bit.


Range Runs Saved measures a player’s ability to get to the ball given where he was positioned, regardless of what happens once he gets there. Here are the leaders and trailers with Range.

Range Runs Saved Leaders and Trailers, 2019
Pos Leader(s) Trailer(s)
1B 17 - Matt Olson -9 - Justin Smoak
2B 16 - Kolten Wong -9 - Y. Sanchez, J. Profar, L. Arraez
SS 23 - Paul DeJong -20 - Tim Anderson
3B 19 - Matt Chapman -16 - Colin Moran
Yolmer Sanchez appears again here, suggesting that the White Sox positioning was crucial in helping him get to balls hit his direction. The Cardinals middle infield and the Athletics corner infield stand out for their range, leading their respective positions.


Throwing Runs Saved evaluates how well the player completes the play after fielding the ball. Here are the leaders and trailers with Throwing.

Throwing Runs Saved Leaders and Trailers, 2019
Pos Leader(s) Trailer(s)
1B 5 - Joey Votto -4 - L. Voit, C. Walker
2B 8 - Yolmer Sanchez -7 - W. Merrifield, R. Odor
SS 11 - Javier Baez -13 - Fernando Tatis Jr.
3B 11 - Matt Chapman -5 - M. Moustakas, V. Guerrero Jr.
Chapman again leads his position, lending credence to the idea that he can afford to be positioned down the line because he has a cannon. Yolmer Sanchez has also appeared on all three lists, showing an excellent ability to record the out once he has the ball. Two touted rookie "Juniors", Tatis and Guerrero, share a deficiency that should be a point of emphasis as they enter Year Two.

There is more information about the changes in a few different places. The 2020 Bill James Handbook has a detailed description and a full leaderboard, the Sports Info Solutions blog has multiple articles on the changes, and the data can be searched and filtered on the Statistics pages on

COMMENTS (7 Comments, most recent shown first)

Thanks guys
6:06 PM Dec 19th
Or click on the link created in the previous comment.
5:46 PM Dec 19th
Rm5: try typing into your browser's address field. Clicking on the link worked for me, but very very slowly, as it attempts to create a secure connection.
5:45 PM Dec 19th
Anyone else have trouble with the fielding bible link? Not sure if it’s a bad link or me trying on the phone.
3:36 PM Dec 19th
So moving Moustakas to second base may help his defense, huh?
12:11 PM Dec 19th
Fascinating analysis! Thanks for the continued effort to analyze defense. I love the stories around Chapman and Sanchez.
9:13 AM Dec 19th

I thought that said FART System.

I'll pass.

9:49 PM Dec 18th
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