The Worst Team Defenses Among Contenders

If you followed along with my Replacement Level Killers series, you’re no doubt familiar with the disheveled state of the Twins. After last year’s epic late-season collapse, Minnesota started slowly, clawed its way back into contention, and then stumbled during a 9-18 June; the team is now 48-51 with 17.5% Playoff Odds, still good enough to qualify for my series highlighting the weakest spots on contenders. Within that series, the Twins made a major league-high five appearances: at catcher, first base, second base, third base, and right field. An underrated part of their struggles is their defense. To the extent that they can still be considered contenders, their glovework stands out as the worst of any playoff hopeful based upon the methodology I used to identify the best team defenses thus far a few weeks ago.
Along with that piece, this is part of my annual midseason dip into the alphabet soup of defensive metrics, including Defensive Runs Saved (DRS), Statcast’s Fielding Run Value (FRV), and our own catcher framing metric (hereafter abbreviated as FRM, as it is on our stat pages). Longtime standby Ultimate Zone Rating has been retired, which required me to adjust my methodology.
On an individual level, even a full season of data isn’t enough to get the clearest picture of a player’s defense. Indeed, it’s not at all surprising that samples of 800 innings or fewer produce divergent values across the major metrics; different methodologies produce varying spreads in runs from top to bottom, spreads that owe something to what they don’t measure, as well as how much regression is built into their systems. Pitchers don’t have FRVs, and DRS tends to produce more extreme ratings (positive and negative) than Statcast. But within this aggregation, I think we get enough signal roughly 60% of the way through the season to justify checking in; I don’t proclaim this to be a bulletproof methodology so much as a good point of entry into a broad topic. Read the rest of this entry »