Jon Lester enjoyed a typically excellent start against the Dodgers on June 20. The Chicago southpaw tossed seven shutout innings in the Cubs’ 4-0 win, which tied the team—momentarily—for first place in the NL Central and lowered Lester’s ERA to 2.10.
That start was also a typically lucky one for the 2018 version of Lester. He fanned just one Dodger batter to become the first pitcher in nearly a full calendar year to throw so many shutout innings with so few strikeouts. That meager total meant a lot of balls in play, on which Lester benefitted from tremendous fortune, even with well-struck knocks: Eight Dodger batted balls had at least a 66 percent chance of becoming base hits, according to Statcast’s calculations derived from exit velocity and launch angle, but only two did. Here’s a sampling of some of L.A.’s should-have-been hits.
he Dodgers’ batting average on balls in play (BABIP) against Lester that afternoon was just .208, against a league-wide season average of .291. One game with a low BABIP doesn’t mean much analytically, but L.A.’s hitters served as just the newest data point in a season-long trend for Lester; in his three starts immediately preceding that Dodgers game, he allowed BABIPs of .125, .059, and .176 in three more Cubs wins. If that sounds like a familiar line about the Cubs, it’s because it’s a callback to the 2016 iteration, and though the team isn’t as good this year, thus far, they’re at least working their BABIP magic again.
The 2016 Cubs, who allowed just a .255 BABIP, set the MLB record by suppressing BABIP to a mark that was just 86 percent of the league-wide 2016 BABIP. (Other teams have had lower raw BABIPs before, but in lower-average eras.) The 2018 version is a touch less extreme, but still the stingiest club in the majors. A .266 mark through Thursday’s games has helped the Cubs outperform their peripheral pitching metrics. That superlative statistic begs the question of how good Chicago’s staff actually is—and how sustainable its surface success might be.
For these purposes, we can turn to fielding independent pitching, or FIP, which strips away the effects of batted-ball luck, among other factors, by focusing on the elements within a pitcher’s control: strikeouts, walks, and home runs. (Of course, those factors are prone to external effects, too. In Chicago’s case, for instance, strikeout and walk totals might be worse than they’d be in a neutral environment because of everyday catcher Willson Contreras, who rates as the worst framer in the majors, with his uneven glove costing Cubs pitchers more than a dozen runs so far this year.) FIP, which exists on the same scale as ERA, better predicts future performance than plain ERA because it’s more likely for extreme batted-ball results to even out than for extreme three-true-outcomes tendencies to reverse course.
That’s a concern for Lester specifically and the Chicago staff more broadly. At the moment, Lester’s 2.18 ERA is 1.90 points better than his 4.07 FIP; the former ranks sixth among qualified starters, while the latter places just 48th. No qualified pitcher in MLB history has finished a season outperforming his FIP by so large a margin, and it’s not as if Lester has extensive FIP-beating history, either: Before this year, his career ERA was 3.51; his career FIP, 3.55.
But it’s not just Lester—all five of the Cubs’ most-used pitchers have allowed fewer runs than their FIP would predict, as have the three most-used relievers and the closer. As a team, Chicago’s ERA is 0.77 ticks lower than its FIP, which would be the largest full-season overperformance for any team since the 1939 Yankees, and the second-largest in MLB history. Even the 2016 Cubs bettered their FIP by just 0.62 points. The 2018 version ranks fourth among all pitching staffs this year in ERA and just 19th in FIP.
That matters when projecting the Cubs’ rest-of-season performance, as they might not be able to continue relying on their current level of run prevention. From 2002 (the first year for which FanGraphs has splits data available) through last year, 21 teams posted a first-half ERA at least half a run lower than their first-half FIP. That overperformance didn’t continue, though, as those teams amassed an average second-half ERA 0.51 runs higher than their first-half mark. Nineteen of the 21 teams saw their ERA rise after the break, despite the entire population of teams since 2002 finishing nearly evenly split between second-half risers and second-half fallers.
In the Cubs’ favor is a staunch defense that could help stave off the pull of regression. Thanks in large part to the flashy gloves belonging to Jason Heyward, Albert Almora Jr., and Javy Báez, the Cubs rank second in the majors in ultimate zone rating and third in defensive runs saved (the two most commonly used advanced defensive metrics). The curious part is that Chicago’s defensive prowess would seem to inform its BABIP fortunes, but rather than their range and ability to turn hits into outs, the Cubs’ fielders have excelled mostly with their arms.
That’s how Kyle Schwarber—newly svelte yet still mashing—rates as one of the best defensive left fielders in the league. The much-maligned defender from previous seasons still makes his share of goofs in the field, but those lowlights belie an impressive overall stat line. First, like Matt Kemp’s in Los Angeles, Schwarber’s range has improved from disastrous to decent. Statcast’s outs above average metric pegged Schwarber as eight outs below average last year, tying him for 297th out of 309 outfielders; this year, he’s solidly in the middle of the pack, at just one run in the red.
More important to Schwarber’s defensive surge is his throwing. As a former catcher—like Bryce Harper, who has saved 14 runs with his arm during his career—Schwarber boasts a powerful arm, and he’s already thrown out eight runners this year, tied for the second-most among all outfielders. DRS credits him with the most productive arm in baseball this year, while Heyward is tied for third place. (UZR flips them, with Heyward first and Schwarber tied for third.)
No team has more effectively prevented runners from taking extra bases, per a Baseball Prospectus stat called “hit advancement runs,” which measures how often baserunners move from first to third on singles, second to home on singles, and first to home on doubles. DRS awards Cubs outfielders 10 runs of value—the equivalent of a full win—from their arms alone; no other team has more than six.
But success with catching or deterring runners inherently involves defensive performance when runners are already on the bases, so that ability doesn’t by itself explain the Cubs’ BABIP success—which prevents runners from reaching base in the first place. Removing the “arm” component of defensive value drops the Cubs from an elite defensive squad into a merely good one, so while defense might explain some of Chicago’s league-best BABIP suppression, it doesn’t account for the whole margin.
The next obvious explanation would be that Chicago’s pitchers have, as FiveThirtyEight put it in a piece about the 2016 Cubs’ BABIP, made their own luck by inducing easily fieldable contact. In 2018, though, the Cubs rate well but aren’t outliers in exit velocity allowed or weak contact induced; there still appears to be a large element of luck in play.
Lester himself is the best example of this phenomenon. His ERA has fallen from 4.33 last season to 2.18 in 2018 despite a sizable drop in strikeout rate and an increase in walks—and, most relevantly here, a seemingly ominous change in batted-ball patterns. Baseball Info Solutions tracks Lester’s soft contact rate as falling from 21.4 percent of all contact last year to just 15.1 this year, while his hard-contact rate has risen from 28.1 percent to 36.2. That’s the opposite direction a pitcher would want, but Lester’s BABIP against has counterintuitively fallen from .310 last season to just .234 this year, giving him the sixth-best rate of any qualified pitcher.
Lester’s “expected” BABIP based on the exit velocities and launch angles he allows is 80 points higher than his actual mark, and his expected stats have barely budged since last season. But among 102 pitchers who have allowed 200-plus balls in play this season, Lester has the third-widest gap between his expected and actual results. As a team, the Cubs have a 43-point gap between expected and actual results—which is, of course, the highest mark of any team.
Those signs all scream regression at the top of their analytical lungs, and for a Cubs team that still trails the Brewers in the NL Central, every little bit matters. Ben Lindbergh calculated that the 2016 Cubs saved in the range of 130 runs from their balls-in-play defense compared to an average team, so even if Chicago doesn’t fall back down to average over the rest of the season, the margins could still be massive through the season’s second half. Except look who’s in second place in BABIP suppression and in greatest FIP overperformance: those very same Brewers. Something must be in the NL Central water—and the division might go to whichever team can make its magic last.
All stats through Thursday.