The discussion on construction of OF zones and the batted ball profile / factors contributing to value is really interesting to me. I think a lot of the nuances are probably unmeasurable or of such marginal value that they are offset by player comfort / meta game strategy / etc, but we’re much closer to being able to put a real value on this kind of thing now than we would have been even 5 years ago.
In addition to the question about relative difficulty of plays in each zone and the distribution of routine / difficult / impossible plays in each zone, another wrinkle would be differences in value of hits prevented. Do difficult or impossible plays in different zones tend to prevent more or less costly hits? Same question as well for holding people to singles, preventing guys from taking the extra base, etc. Intuitively it seems like the very hard plays in CF probably have the most value, followed by RF (due to more triples than LF and also more opportunity to prevent first-to-third chances). But maybe that’s wrong. Maybe a significant chunk of the hard-but-makeable plays in CF end up being stolen singles (this would also be impacted by the OF’s original positioning). On the infield, you might actually find that the per-play value of exceptional plays at the corners is higher, due to XBH prevention, but they have so much fewer chances that middle infield is still vastly more important. (And maybe some or all of these questions are already answered, as best as possible, in the formulas or historical data for DRS, which I don’t really know on a deep level).
I guess the real answer is that eventually we’ll have a Statcast-infused DRS-like measure that incorporates both difficulty and changes to run expectancy, while also adding original positioning and hopefully some situational, WPA-type weighting to the mix. At that point we can look at all kinds of interesting data, including impact of defensive positioning on play difficulty, relative value of defensive tools in run prevention, both generally and at different positions, and where/how defenders accumulate value over average.
This last bit is maybe the most interesting part to me… do some guys prevent runs in big chunks based on range or spectacular throws, while others suppress them consistently over time by preventing XBHs and denying the extra base? Where are the best opportunities for run prevention over the life of a season – is it possible to identify what types of situations combine hard-but-makeable plays with impact on run expectancy and then figure out which skills are most important in making them? Are there categories of plays that we tend to overrate relative to their impact on run expectation, or others that we undervalue?
Maybe someday we’ll learn definitively that JBJs short-area quickness and incredible jumps actually create a greater marginal improvement over Mookie at the corners than in CF, where Mookie’s top-end speed and range close some of the skill gap. And that the types of “extra” plays JBJ makes in the corners are weighted towards chances with a relatively high impact on run expectancy, and therefore outweigh the reduced chances in the corners relative to CF.
Probably not though. They’ll probably say “duh, play JBJ in CF, you big dummy.”
