New Diamondbacks pitcher Zach Davies isn’t a household name. His 6-foot, 180-pound frame is as unassuming as it comes for a pitcher, and he was drafted in the 26th round out of Gilbert’s Mesquite High School — roughly 20 miles away from his new home ballpark in downtown Phoenix.

Not many players reach free agency at 28 years old, though. Davies has had a nice career with a 4.14 ERA, 1.33 WHIP, 17.3 percent strikeout rate and 7.8 percent walk rate as a starting pitcher.

Unfortunately for the Chicago Cubs — and concerned Diamondbacks fans — he struggled mightily in 2021. Davies posted a 5.78 ERA, 1.60 WHIP and a career-high hard-hit rate of 43.3 percent, per Baseball Savant. Despite making a full 32 starts, he tossed just 148 innings, averaging well under five innings per start. By all accounts, it was the worst season of Davies’ career. 

On the positive side, Davies didn’t lose meaningful velocity or movement on any of his pitches. Spin rates were down slightly across the board, but probably not enough to make a difference. So, what went wrong, and how can Davies get back on track?

Today’s starting pitcher Zach Davies on what he is currently working on in this short spring training and what working with the @Dbacks coaching staff has been like so far. pic.twitter.com/CxrWlTTnBA

— PHNX Diamondbacks (@PHNX_Dbacks) March 29, 2022

Let’s start by defining who Davies is as a pitcher. He’s certainly not overpowering, relying primarily on an upper-80s sinker and an upper-70s changeup. Those two offerings comprised a career-high 85.4 percent of his pitches in 2021. The other 14.6 percent was a nearly even split between his curveball and cutter.

Among pitchers with 140 or more innings pitched, Davies had the highest walk rate in baseball at 11.2 percent. It was the first time since his rookie season that Davies walked more than 7.6 percent of opposing hitters.

The main culprit appears to be Davies’ changeup. When behind in the count, Davies landed his offspeed pitch in the zone 37 percent of the time, compared to 50 percent in 2020. Perhaps that explains why Davies threw significantly more sinkers (55.5 percent) than changeups (34.2 percent) when behind in the count. In 2020, he actually threw more changeups (47.9 percent) than sinkers (37.7 percent) in those situations, theoretically because he felt confident landing either for a strike when needed.

That’s not to say that Davies’ changeup was ineffective in 2021. His 36.7 percent whiff rate on the pitch was more than adequate. The pitch moved essentially the same way that it did in 2020, and it was pretty filthy then.

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Unfortunately, hitters swung at it 51.9 percent of the time in 2021 compared to 65.4 percent in 2020. That dip led to fewer strikeouts and more walks. 

When opponents made contact with the changeup, they did more damage than they had done in the past, batting .258 with a .472 slugging percentage and a .332 wOBA. Batted ball metrics suggest that Davies was a bit unlucky in that regard, so those numbers aren’t particularly alarming.

Opposing hitters’ numbers against Davies’ sinker, however, are quite alarming. In 318 plate appearances that ended on the sinker in 2021, opposing hitters hit .305 with a .500 slugging percentage and a .399 wOBA. Unlike with the changeup, batted ball metrics suggest those numbers were not a fluke.

Beyond the fact that hitters were probably more geared up for it than they’ve been in the past (he threw far more sinkers in hitter-friendly counts than he has in the past), Davies also struggled to keep the pitch down in the zone. That can be seen in the following heat maps for Davies’ sinker for 2020 (left) and 2021 (right):

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It’s possible for finesse pitchers like Davies to work effectively up in the zone, but the sinker probably isn’t the right pitch to fill that role.

Ultimately, there’s really no reason to believe that Davies’ sinker-changeup combination can’t function in a major-league rotation. Davies’ biggest keys to success in 2021 appear to be throwing more changeups for strikes and keeping the sinker down in the zone.

Doing so will be easier said than done, but as we always say with pitchers around here, just wait till Brent Strom gets his hands on ‘em. It will be like magic.

Strom helped sinker-baller Dallas Keuchel win a Cy Young winner back in Houston in 2015. Perhaps he can help Davies take a step in that direction in 2022.

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Top image: Michael McLoone/USA TODAY Sports