Zach Davies has never made a top 100 prospects list. He has never topped 92 mph on the radar gun. Yet, when he was traded from the Baltimore Orioles to the Milwaukee Brewers in exchange for Gerardo Parra, it turned out to be a deal that Orioles GM Dan Duquette would always regret. With elite command and an uncanny ability to change speeds and keep hitters off balance, he has found major league success in the last season and a half with the Brewers. Davies is 6’0”, but weighs just 150 lbs., however, despite his skinny frame, he has shown surprising durability since joining the Brewers rotation. In his two seasons in Milwaukee, Davies has made at least 28 starts in both campaigns. Despite a relatively low walk rate of 15.7%, he has proven to have elite contact management skills. In fact, his opponent exit velocity of 85.0 mph ranks 154th of 176 qualified starters this season.
Davies official coming out party was really last season when he went 11-7 with a 3.84 ERA and a 2.7 WAR, which was two wins higher than any other Brewers starter that year. With breakout seasons by Jimmy Nelson and Chase Anderson, the Brewers now have three young controllable right-handers that could be slotted in as the #1, #2, and #3 starters for a long time.
Despite his superb start with the Brewers last season, his sophomore year with the club didn’t go start out as smoothly. Having never thrown more than 110 innings above Double-A, Davies threw a total of 172 innings between the minors and majors in 2016, so perhaps he was suffering some arm fatigue. Whatever the case, in between April and June, Davies was one of the worst pitchers in the MLB, giving up 14 HRs and striking out less than 15% of the batters he faced, while posting an ugly 5.08 ERA with a 4.71 FIP.
We didn’t have to look far into his pitch usage numbers to realize what had changed. After throwing nearly 25% changeups throughout his career and never giving up higher than a .384 SLG% in any one year against that pitch, it looked as if he had lost feel for it during the early months of the season. From the start of the season until July 14th, Davies was only throwing his changeup 16.08% of the time which was nearly 8.0% less than he had thrown it in any of his first two years. For the first time in Davies career, when he did throw his string puller, it was getting raked. In those first 19 starts, batters had a .294 batting average and .451 SLG% against Davies changeup, which were far and away career highs against him.
From July 19th forward (I acknowledge the arbitrariness of the start point), Davies has been the undisputed ace of the much improved Brewers rotation by pitching to a dazzling 1.75 ERA and holding hitters to a meager .575 OPS. Davies is still only throwing his changeup roughly 15.0% of the time, but opposing hitters are managing just a .222 SLG% when they do choose to offer at it, which is further evidence that Davies best weapon is back, During this time span, his changeups whiff rate is also 19.83%, which is over seven percent higher than the whiff rate on his next closest pitch. His changeup also improved dramatically according to some of the more advanced Statcast date. In the first 19 starts of the season, the wOBA against Davies changeup was .364, but hitters have yielded just a .221 wOBA since.
While rediscovering his changeup was the primary reason for Zach Davies in season turnaround, part of the reason that he turned his season around can be chalked up to good old fashioned regression. In his first 19 starts, he was hurt by a 16.1 HR / FB% as well as a 66.7% strand rate. Since then, he has been fairly fortunate by benefitting from .281 opponents BABIP, which could also be due to a 24.8 Hard% rate and a 74.2 LOB%.
Another interesting finding that could have had an impact on Davies transformation into one of the most reliable Brewers starters was his fastball location.
Take a look at a heatmap of the fastballs he threw in his initial 19 starts.
This picture is taken from the catcher’s perspective so he was trying to pound the outer half of the zone against lefties and come in to righties. It shouldn’t be a surprise that hill pull% to right handers was a career high of 41.0% and putting up a 1.161 OPS on balls that were pulled.
Since then, his fastball location has changed dramatically as he is now throwing the majority of his two-seamers are the inner half of the plate to lefties. By keeping his soft fastball away from the power zone of right handed hitters and throwing hard in and soft away to lefties, Davies has found some success.
Here is a look at Davies fastball location starting on July 14th.
Seemingly at the drop of a hat, Davies began throwing his two seam fastball to the other side of the plate in an attempt to front door left handers and freeze righties by running a fastball across the outer half. If Davies can continue to suppress the power of right handed hitters and also using his dominant changeup to help retire lefties, he very well could lead the Brewers rotation into October.