Ben Clemens examines how Yandy Diaz changed his approach at the plate over time. He went from an extreme ground ball rate to getting more loft and power to going back to an extreme ground ball rate, with a twist. His current ground ball rate is an adjustment to the way pitchers approach the Rays star, and part of the adjustment sends the ball to the opposite field, where he is more likely to find a hole:

In other words, going the other way on grounders seems to be a skill batters can truly possess. That’s not to say it’s guaranteed to continue, or that this is even what Díaz should be doing. It certainly doesn’t mean he can keep up his current stratospheric rate. At present, though, it feels like a chess match. Pitchers learned last year that Díaz wants to crank the ball in the air. They countered with a straightforward plan: throw it to a place he can’t pull.

Díaz’s counter to that counter is, for now, holding the day. He’s doing his best to wait for a pitch to hit — with less than two strikes, he’s spitting on those pitches, swinging only 36.1% of the time — righty batters swing 55.2% of the time in similar situations. When the count reaches two strikes, he’ll defend by trying to punch the ball the other way — he’s swung at 25 of 27 such pitches on the year, 92.6%.

For pitchers, it hasn’t been a sustainable equilibrium. They’ve found the zone on only 43.4% of pitches per Statcast, the lowest zone rate of his career by four percentage points. You can’t beat Yandy Díaz without coming into the strike zone, because he’ll just walk, and that’s exactly what’s been going on.

FanGraphs.com

Over the last decade, certain players were killed by shifts, as they were unable to adjust to taking pitches the opposite way. Part of it was the inability to relearn how to hit, but I also believe part of it was a reluctance to trade power for on-base average. Runs are exponential in OBP, however, go doing a better job of getting on base is a good thing. Diaz shows us how.