Nothing much has changed about Simmons except that he is hitting the ball a little harder this year and his HR rate has spiked along with just about everyone else in baseball it seems. Otherwise, he's basically profiling about the same as a hitter. Same GB/FB -- relatively similar walk and k rates.

His BABIP is up this year probably in part because he is hitting the ball harder.

But he has displayed this kind of power before albeit it was an outlier season where things otherwise weren't going that well for him.

This seems like natural progression, plus some good fortune, plus maybe a juicy ball.