A Look at the Best Team Defenses Thus Far

The Rangers haven’t played in the postseason since 2016 (and haven’t even finished above .500 since then), but they’ve been atop the AL West for almost the entire season and are now 49–31, with a six-game lead over both the Angels and Astros. They own the majors’ largest run differential (+160) as well as its most potent offense (5.98 runs per game), and thanks to a revamped pitching staff, they’re third in run prevention as well (3.98 per game).
An underrated part of that run prevention is the team’s defense. By my evaluation of a handful of the major defensive metrics — Defensive Runs Saved, Ultimate Zone Rating, our catcher framing metric (hereafter abbreviated as FRM, as it is on our stat pages), and Statcast’s Runs Prevented (which I’ll call Runs Above Average because their site and ours use the abbreviation RAA) and catching metrics for framing, blocking, and throwing (which I’ll combine into the abbreviation CRAA) — the Rangers rate as the majors’ second-best defensive team thus far this season. The Brewers, who are in the midst of a dogfight for first place in the NL Central, are the only team ahead of them.
I’ll explain the methodology behind this conclusion below, but first a bit more about the Rangers. With Jacob deGrom sidelined after just six starts due to a UCL tear that resulted in Tommy John surgery, the team’s pitching staff has the 13th-lowest strikeout rate in the majors (22.2%), but it also has the third-lowest BABIP (.274), in large part thanks to the team’s fielders (the pitchers haven’t been especially good at preventing hard contact). Second baseman Marcus Semien is the only past Gold Glove winner of the bunch, but he’s one of five Rangers defenders with at least 5 DRS thus far, along with first baseman Nathaniel Lowe, outfielder Travis Jankowski, right fielder Adolis García, and catcher Jonah Heim. Lowe, Semien, and center fielder Leody Taveras all have at least 4 RAA, and Heim is 3.7 runs above average in FRAM and +6 in CRAA.
Not all of the metrics are as favorable for the aforementioned players, but it’s worth noting that of the 10 Rangers with the most defensive innings played at a single position, the only negative run ratings are those of shortstop Corey Seager and left fielder Robbie Grossman (both -2 RAA) and Lowe (-2.6 UZR); every other Ranger with at least 161.1 innings at a position rates as average or better. To be fair, 161.1 innings is still a small sample, and for that matter, even the 697.1 innings of Semien at second is less than ideal for a full evaluation, though we can feel better that his DRS, UZR and RAA don’t wildly contradict each other. Particularly at this stage of the season, with teams having played 78–83 games, it’s better to bear in mind the range of values reflected in an individual’s fielding metrics rather than focusing on a single one. To return to Semien: his 6 DRS and 5 RAA are contrasted by his 0.8 UZR; it’s not a matter of which one is “right” so much as it is understanding that he shows up somewhere along the spectrum from slightly above average to solidly above average.
Given all of this alphabet soup dished out in small servings, I set out to look at team defense by aggregating the aforementioned metrics, which reflect differing methodologies and produce varying spreads in runs from top to bottom that owe something to what they don’t measure as well as how much regression is built into their systems. Pitchers don’t have UZRs or RAAs, for example, and the catching numbers are set off in their own categories rather than included in UZR and RAA. I’ve accounted for the varying spreads, which range from 86 runs in DRS (from 42 to -44) to 25.6 runs in FRM (from 13.8 to -11.8), by using standard deviation scores (z-scores), which measure how many standard deviations each team is from the league average in each category. I don’t proclaim this to be a bulletproof methodology so much as a good point of entry into a broad topic. The Rangers, who entered Wednesday (the cutoff for all of the data below) tied with the Blue Jays for the major league lead with 42 DRS, score 1.86 in that category but “only” 1.37 in UZR and 1.13 in RAA (13.4 runs in the former, 10 in the latter, both fourth in the majors), and so on. Read the rest of this entry »