Batting average on balls in play comes with a defensive mirror image, and that’s defensive efficiency.
The rise in BABiP that has come with rules changes for 2023 means a lower percentage of balls in play are turned into outs.
BABiP is up from .290 in 2022 to .297, helping fuel an overall rise in batting averages from .243 to .248. DefEff has dipped from .697 to .691, meaning 69.1% of batted balls become outs.
The Cubs and White Sox are near opposites on the DefEff scale. For all their inconsistencies at the plate and on the mound, the Cubs have been above average in converting outs with a .699 DefEff, the ninth-best in the majors. With a .681 DefEff, the Sox rank 21st.
That’s similar to their ranks in Baseball Info Solutions’ defensive runs saved, as listed at Baseball-Reference.com. Runs saved takes into account factors including how hard the ball is hit, where it’s hit, how often fielders make plays on similarly hit balls, arm strength and more.
Average fielding is the base for runs saved, and an average team would have zero. The Cubs are 10th in the majors with three, and the Sox are 27th at minus-15.
One way to look at that is Cubs fielders have saved pitchers three runs, but Sox pitchers have allowed 15 more runs than they would have with average defense.
DefEff is a team stat, with no individual rankings. Runs saved starts with individuals, and their runs saved above or below average are added to calculate a team total.
Despite the team totals, the best defensive player in Chicago so far this season works on the South Side. Sox center fielder Luis Robert Jr. ranks second in the majors with 10 runs saved, two behind Padres second baseman Ha-Seong Kim.
Robert’s defensive prowess is part of the reason he’s also the city leader in wins above replacement with 2.7 at Baseball-Reference and 2.1 at Fangraphs.com.
Seby Zavala also shows up well above average with five runs saved, but fellow catcher Yasmani Grandal is at the bottom of many below-average Sox defenders at minus-8.
On the North Side, the middle of the infield — with Dansby Swanson at shortstop and Nico Hoerner at second base — has been as good as advertised. With six runs saved, Swanson is tied for 11th in the majors and tied for the lead among shortstops with the Rays’ Wander Franco.
Hoerner is right behind with four runs saved, tied for 27th overall.
Oddly, left fielder Ian Happ, a Gold Glove winner with 14 runs saved in 2022, is on the negative side in the early going of 2023. With minus-5 runs saved each, Happ and right fielder Seiya Suzuki are at the bottom of the Cubs’ list.
For Happ, that could just be a case of early-season weirdness that comes with small samples. For the Sox, weak defense continues a disturbing trend after they ranked 23rd in DefEff and 28th in runs saved last season.
