Cubs’ defense is not as bad as it looks; White Sox are different story

Cubs pitchers have been backed by one of baseball’s best, most efficient defenses the last four years, during which the team has won no fewer than 92 games in a season.

This season, through Sunday, the Cubs have made 36 errors, most in the National League and third in MLB behind the Mariners (53) and White Sox (37). Their .979 fielding percentage is fourth-worst in baseball, beating only the Mariners (.971), White Sox (.976) and Mets (.978).

Do the Cubs really have one of baseball’s worst defenses — a question raised Sunday during ESPN’s telecast of their 6-5 victory over the Nationals?

Metrics more advanced than fielding percentage say no. The Cubs have been about average, while the Sox rank nearer the bottom in defensive efficiency, Fangraphs’ defensive runs above average and Baseball Info Solutions’ defensive runs saved.

The idea is that an error is a play not made on a ball in play, the same as a base hit is a play not made. Whether the label is “hit” or “error” doesn’t matter in evaluating how well a defense turns balls in play into outs.

Baseballsavant.com shows the Cubs with a .699 fielding efficiency rating, meaning they have turned 69.9 percent of balls in play into outs. That’s tied with the Orioles for 15th of the 30 teams in MLB and ranks eighth of the 15 NL teams. When it comes to turning runs into outs, the Cubs have been a middling team.

The Sox, at .682, are 26th in MLB and 13th in the American League.

Fangraphs (which uses Ultimate Zone Rating plus a positional adjustment) and BIS try to dig deeper. Every batted ball is tracked for factors including location and speed, and the outcomes are compared to similar plays for other fielders. Outfielders’ arms and middle infielders’ ability to turn double plays are among other factors tracked. Average play is set at zero, so positive numbers signify above-average play and negative numbers below-average play in both Fangraphs’ DEF — the label on its site — and BIS’ defensive runs saved.

In both, the Cubs are about an average team, barely on the positive side. Their four defensive runs saved rank eighth in the NL and 16th in MLB, while their 5.7 DEF at Fangraphs is sixth in the NL and 10th in MLB.

The Sox are on the negative side at minus-16 DEF, 29th in MLB and 14th in the AL, and minus-13 runs saved, 23rd in MLB and 11th in the AL.

In what should be no surprise, the Cubs have been strongest at shortstop, where Javy Baez’s eight runs saved rank second in MLB. The Sox have positive numbers only in center field, where Charlie Tilson (3), Adam Engel (3) and Leury Garcia (minus-2) have combined for three runs saved.

As a contending team, the Cubs would like to cut the errors. But are they one of the worst defensive teams in baseball? No, they’re right around the MLB midpoint.