zack-wheeler-3.png
USATSI

When the Philadelphia Phillies signed Zack Wheeler to a five-year deal worth $118 million over the offseason, they probably would have paid extra to ensure he would enter the stretch run with a 2.20 ERA and a clean bill of health. Indeed, Wheeler has been one of the most productive pitchers in the majors this season. 

Coming into his start on Monday, he ranked fifth in Wins Above Replacement among National League pitchers, just ahead of teammate Aaron Nola. Yet the most notable aspect of Wheeler's year is not that he's pitching well; it's how he's pitching well.

It was a widely accepted premise heading into last offseason that Wheeler had more to offer than his statistics suggested. We explained as much last trade deadline, and doubled-down on that belief when we ranked him as the seventh-best free agent. Here was part of the reasoning:

Wheeler does have the innate characteristics teams like in their pitchers: velocity, spin, swing-and-miss secondaries, and so on. It's perhaps worth noting that Wheeler's best month per OPS against came in September, when he threw more four-seamers than sinkers. His next team might ask him to continue that trend -- and to pitch up in the zone more often, where his natural rise can lead to more whiffs.

Based on the combination of Wheeler's performance to date and the above observation, you'd be on steady ground to suggest the Phillies encouraged him to elevate his heat more frequently. You'd also be wrong, because Wheeler has veered away from the expected path and has instead turned into groundball-oriented contact manager with one of the lowest strikeout rates among qualifiers. As of the weekend, his strikeout rate (5.8 per nine) ranked 40th out of the 43 pitchers with 40-plus frames. His groundball rate (55 percent) ranks fifth, essentially in-between dusty worm-killer Dallas Keuchel and Dustin May, possessor of the 98-mph turbo sinker.

The drivers behind Wheeler's new approach are his fastballs. Last year, his four-seamer generated grounders on less than 40 percent of his batted balls, while his sinker checked in at 47 percent; this year, those marks are up to 53 percent and 67 percent. His four-seamer has changed in its movement profile, sinking more and running less, and its reduced spin efficiency indicates the spin is contributing less to the movement. He's locating the pitch lower on average, which suggests the tweaks are intentional, whether they're grip-related or what have you.

So, that's what Wheeler has changed -- are those changes for the better? Based on his performance, it seems like it. Not only is he limiting quality contact, but the contact he is permitting tends to be of the groundball variety. Additionally, there's reason to believe he'll miss more bats heading forward. Take a look at some of his underlying measures, via Statcast:

Season20192020

Swing%

50.6%

50.8%

Chase%

30.8%

30.5%

Whiff%

23.1%

22.1%

Wheeler isn't prime Nick Blackburn all of a sudden. He's coercing swings and chases and generating whiffs about as frequently as he did last season. It's just not showing up in the strikeout column yet -- even if it should, seemingly, in due time.

As such, the Phillies should be thrilled with their marquee free-agent signing, and Wheeler should be happy that he's found a way to tap into his upside -- even if it's not the way most people anticipated.