Astros 2018 Positional Defense—Infielders

Although I touched on a few defensive stats last week, FanGraphs has a great primer on a variety of metrics used to measure fielding that can help both the novice and experienced observer alike. As I mentioned last week, Defensive Runs Saved (DRS) and Ultimate Zone Rating (UZR) are not great tools to measure defense for a single season (they require larger samples to normalize), but they are referenced often and are certainly better than standard stats like fielding percentage or errors. Thus, I will not refrain from using them to examine player performance (for which they are better than team defense) in this article.

A quick definition of DRS is that it is used to rate players as “runs” above or below average on defense. Essentially, DRS uses a few different calculations (e.g., bunt runs saved, double play runs saved, outfield arm runs saved) to capture how much a fielder’s defense helped his team win. UZR is fairly similar but offers us a perspective on a player’s defense relative to league average at his position. A caveat for each of DRS/UZR is they don’t factor in shifts or defensive alignment, so neither will be as valid a measurement for a team like the Astros as they may be for other clubs. As such, I will accompany my analysis with other defensive stats, like Inside Edge Fielding and a metric called Defensive Runs Above Average (DEF), which I’ll get into later. This week, I will review individual defensive metrics for Astros infielders in 2018. So let’s get started.

Alex Bregman was great in the field last year, right?

Although he had a breakout year at the plate, the defensive metrics were somewhat mixed on him (which gives me further evidence there is still a lot of work to be done with defensive statistics). Bregman converted 3.9% of his “Remote” chances into outs, which—while admittedly small—was still fourth-best in the league. He also made 25.0% and 47.6% of his “Unlikely” and “About Even” chances, respectively, which were Top 10. Conversely, he was -6 DRS and had a negative UZR (-3.1) and UZR/150 (-5.1), which is scaled on a 150-game basis for ease of player comparison. He was closer to Miguel Andujar (-14.0) than Matt Chapman (13.1) in Defensive Runs Above Average (DEF), which measures a player’s defensive value relative to league average (Bregman was -1.0). Yikes. But the thing is, some of Bregman’s spectacular plays may be explained by his atypical positioning, which DRS and UZR don’t take into account.

Statcast offers a cool perspective on infielders’ alignment over the course of a season using a metric called “Angle” (check it out here). Angle is defined as -45° being the 3B line, 0° being up the middle from home plate to center field, and +45° being the 1B line. Bregman played at an average angle of -35° angle in 2018, which was one of the closest to second base amongst regular third baseman (min. 500 plate appearances) and with an average depth of 116 feet. Bregman had by far the most plate appearances in the shift while at the hot corner (477, nearly half of his time at third base), so this makes sense. For comparison, Oakland’s defensive whiz Matt Chapman played at an average angle of -37° and depth of 121 feet. Both guys made an equal number of plays Out of Zone (OOZ) in 2018, however, which is interesting.

Even though Carlos Correa was hurt most of the season, he made a ton of plays at a premium position. Correa led all shortstops in percentage of “Unlikely” and “About Even” plays made—albeit, in fewer chances than many of his counterparts, primarily due to his extended absence. Correa’s DRS (-4) was mostly affected, like Bregman, by a low plus/minus runs saved (rPM), which evaluates a fielder’s range and ability to convert a batted ball into an out. Huh? Didn’t I just say he led SS in “Unlikely” plays?

Yes, he did. That video, of course, consists of Correa’s highlights in 2018, but his range looks plenty good to me. And that was with an ailing back for most of the season. As I’ve mentioned a few times, the Astros generally seem to be negatively impacted by DRS and UZR because they don’t account for positional alignment. That just means any analysis of Astros defense must be supplemented with other metrics.

Like Correa, Jose Altuve was limited by injuries for substantial portions of the 2018 season. Altuve still had 1 DRS—highest of all Astros infielders—primarily due to his ability to save runs with the double play. Altuve had a rGDP of 3, tied for highest in MLB amongst second basemen.

He, like the other Astros’ infielders, was hurt by rPM (-3). Altuve made a fair amount of plays OOZ (75) for a guy that missed some time, though his UZR (-3.2) and UZR/150 (-5.9) were near the bottom of his position. Altuve didn’t convert any of his 11 “Remote” opportunities into outs, though this play sure seems like it could be classified that way.

Anyway, Altuve was middle-of-the-pack across the other Inside Edge Fielding categories. Altuve has generally been a reliable second baseman in the field who has shown improvement over the years. I’d expect that to continue next season, so long as the knee concerns don’t linger. Maybe he’ll show us this kind of sorcery again, too.

The Astros had a bit of a platoon at first base, with Yuli Gurriel primarily playing the position and Tyler White sprinkled in, at times. Because White didn’t log a ton of innings at first base (and the stats would be untrustworthy), I’ll focus on Yuli’s value. Yuli’s defense has been a knock since entered the Bigs in 2016, though I’ve always found that odd considering he mostly played third base in Cuba. I figured his transition to first base would maximize his abilities rather than hinder him. Again, Yuli is another case where the stats conflict regarding his defense. He had one of the lowest UZR/150 (-5.3) amongst first basemen and made the least amount of plays OOZ (6). He also had a -9.6 DEF, which was actually better than highly-regarded first basemen (on defense, at least) Chris Davis (-10.4) and Eric Hosmer (-14.4). Although Yuli didn’t make many plays OOZ, he led first basemen in “Remote” and “Unlikely” plays converted into outs (small sample disclaimer: these opportunities are very limited for first basemen). It was the “Likely” plays where Yuli lagged behind the rest of the league. He only converted 60% of those into outs, lowest at his position.

Lastly, newcomer Aledmys Diaz grades out similarly as an infielder to Marwin Gonzalez, which CRPerry wrote about. Using DRS and UZR, Diaz has been quite a bit better at third base than shortstop, though he will likely get playing time all over the diamond if Marwin (who I’ll touch on in the outfield edition of defense) remains unsigned. The versatility Diaz will afford the Astros probably outweighs his prowess at any one defensive position, though I wouldn’t expect to see him at short too much in 2019 if the Astros can avoid it (Bregman or maybe even Yuli is more likely).

In summary, the eye test says the Astros were relatively strong defensively in the infield last year. Analytics seem to indicate the Astros’ infield was one of the lower-rated units in baseball. I think the metrics are actually trying to grade the Astros as an average defensive infield, but if we consider the flaws of some of the defensive stats it may just be that the Astros aren’t being measured accurately. Bregman, Correa, and Altuve each led their respective position in plate appearances in which the defense was shifted, and Gurriel was second at his position. Thinking beyond DRS and UZR, the Astros are usually well-positioned defensively and prepared for situations. Couple that with the elite starting pitching—which is an important factor for defense because it begets the quality of contact produced on batted balls—the Astros had last season and I think we can expect a solid defensive infield again in 2019.