It started with J.P. Crawford. I was digging into some statistics and noticed Crawford ranked as the worst baserunner in the majors according to Baseball-Reference's baserunning metric at minus-5 runs below average. How could that be? Crawford isn't slow. Well, he's not slow, but he was 3-for-9 stealing bases and he was not aggressive in taking the extra base, such as going first to third on a base hit. Maybe he just had a bad season on the bases, or maybe this is the sign of a bigger issue.
Anyway, that led to more digging for more unique numbers: via Baseball-Reference, "The Bill James Handbook," FanGraphs, Statcast.