Remember when we said Moustakas' 57.0% swing rate was only second on the Royals? That's because catcher Salvador Perez currently has the lead with a 58.4% rate. Calling Salvy a free-swinger isn't anything new based on recent performance, but this year's number is currently dwarfing the 54.8% he posted between 2014 and 2016.

Like his fellow teammate, Perez has also used this extra aggressiveness to put an additional charge into his power numbers. The backstop has already clinched his third consecutive 20-homer campaign, and with 21 bombs overall, he's just one off his single-season career high, which he set last year. The biggest difference is that it took him 546 plate appearances to get there in 2016, but he's on the verge of meeting that number in 2017 after just 388 plate appearances.

Not surprisingly, his .234 ISO is also on pace to be a career best, while his 111 wRC+ and .342 wOBA would be his highest marks since 2013 if the season ended today. His batted-ball profile certainly helps, and what particularly stands out are his fly-ball rate (48.8%), pull rate (54.6%), and hard-hit rate (39.3%).

Those are all the best rates he's produced thus far in a season, and provide an explanation behind his power surge. He's not only putting the ball in the air more than ever before, but he's hitting it harder more often than ever -- between 2015 and 2016, his hard-hit rate on fly balls was just 30.0%, but it's currently at 41.0% in 2017.