Dylan Cease Has Improved This Season

The White Sox have built a commanding lead in the American League Central. They’re now 10 1/2 games ahead of second-place Cleveland and have a 99.9% chance of going to the playoffs according to our Playoff Odds. They were heavily favored to win the division going into the season, but the club has had to overcome some significant adversity (most notably early season injuries to Eloy Jiménez and Luis Robert) en route to the secure position they currently hold. And even beyond injuries, the roster was not without its questions, with one big one being how Dylan Cease would perform in his first full season in the rotation.

Cease’s 2020 campaign produced mixed results. On the surface, his 4.01 ERA, 5-4 record, and 44 strikeouts across 58.1 IP was decent. But he drastically outperformed his expected statistics, and it was hard to imagine he could maintain that ERA given his elevated walk rate (13.3%) and home run rate (1.85 HR/9), not to mention his 6.36 FIP. Cease has always had great stuff. As a prospect, his fastball graded as a plus to plus-plus pitch, with his breaking ball sniffing 60-grade territory; the question was how well he could control and command his repertoire. And while his 2020 peripherals suggested his performance this season would regress, there was a lot of optimism surrounding Cease prior to the start of the season. In spring training, Yasmani Grandal stated, “I feel like if we get him to where we see him going, this guy could be a Cy Young finalist — he could possibly be a Cy Young winner.”

There isn’t a strong argument for Cease as a Cy Young candidate, and I’m not going to try to make one. His ERA is nearly identical to last season’s (3.99). Grandal was not blowing smoke though; Cease has made huge strides this season. He has combined with Lance Lynn, Lucas Giolito and Carlos Rodón to form a formidable rotation; the White Sox lead the AL in WAR from starting pitchers:

Cease has contributed 3.1 WAR on his own and while his ERA hasn’t changed, his FIP certainly has, dropping to 3.36, all while showing improvement in each of the walk, strikeout, and home run categories. I already mentioned that his walk rate last season was not good. Despite an average fastball velocity of 97.6 mph, his strikeout rate was in the 14th percentile according to Statcast (also not good). His strikeout-to-walk ratio (1.29) was second-worst in the league among pitchers with at least 50 innings pitched. He has flipped the script this season:

His walks are way down; he has cut his rate by over three percentage points to 9.5%. His strikeout rate has also improved a ton, going from 17.3% to 30.8%. He’s managed to climb out of the league’s cellar to a respectable 3.24 K/BB, which is well above the league average of 2.68. So how has he done it?

His best pitch, the four-seam fastball, is moving a lot more than it did in 2020. Last season, he had a relatively flat shape to his fastball and hitters had little trouble making contact. That’s changed this season. He’s always had a high-spin fastball, but now he’s harnessing the movement of that pitch to induce swings and misses up in the zone. The heat maps below show hitters contact rate over the last two seasons (2020 is on the left, 2021 on the right):

In 2020, the red area indicating the highest contact rate covers the middle of the zone as well as the top left; that’s a lot of real estate in the top third of the zone. Typically fastballs with effective rise elicit whiffs when they are located in the top part of the strike zone. This season, hitters are swinging and missing at many of these same pitches they were making contact with last season (the red area representing high contact for 2021 covers much less area in the top third of the zone). Cease feeds hitters a steady diet of fastballs; he throws it nearly half of the time. This season, his fastball has generated swings and misses 13% of the time, a bit above his 8.3% swinging strike rate from last season; in the top of the zone that increase is even more pronounced, with a 20.2% swinging strike rate compared to just 10.7% a year ago. Cease is also generating more movement from his high-spin fastball this season. According to Statcast, his fastball has 2.1 inches more run than the average four-seamer; that is an elite rising fastball. The added movement is the result of some mechanical adjustments he’s made to increase the pitch’s spin efficiency. Statcast’s spin-based active spin rate calculation estimates that 89.6% of the spin on Cease’s four-seamer is “active,” compared to 82.8% in 2020.

With the mid-season memo on sticky stuff enforcement issued by MLB on June 15, there is a bit of nuance related to the spin rate on Cease’s pitches. As Jeff Zimmerman noted last month, for a stretch following the memo, the spin rate on each of Cease’s main three offerings decreased significantly. I’ve updated the chart to check in on how Cease has fared since then, and it looks like he’s managed to adjust.

While the spin rate for each pitch still falls short of the season average prior to the enforcement of the rules on foreign substances, they are much closer than they were in the weeks immediately following the memo.

As much as the four-seamer has improved, its performance hasn’t really changed much in terms of runs created. Sure, the strikeouts are up but hitters still have a .345 wOBA against the fastball compared to .383 in 2020. If we focus only on batted balls, the gap narrows even further, with a .366 wOBA against this season compared to .375 last year. So while there’s some improvement, the fastball is still being hit pretty hard. The area where Cease is really making gains is with his secondary pitches.

Collectively hitters have managed a .243 wOBA against his secondary offerings in 2021, this compared to a .214 xwOBA on the pitch. It was a different situation last season, where luck was on Cease’s side and hitters underachieved a .343 xwOBA by hitting for a wOBA of just .311. He’s located the pitches similarly this season, but the improved fastball has made his slider and curve in particular more effective. Hitters are chasing his secondary pitches out of the zone 35.3% of the time, up from 28.3% in 2020. In two-strike counts, he’s inducing a swing and miss 21.5% of the time when throwing a secondary pitch out of the zone, nearly twice as often as last season.

(Interestingly, Statcast’s Run Values, which evaluate pitch quality based on the run scoring potential of the situation for each pitch thrown, show Cease’s fastball as having the biggest difference compared to 2020, improving by 13 runs. Statcast estimates that his fastball has prevented an additional five runs over the expected run value so far this season. His only secondary offering that has shown improvement to anything like this extent is his changeup, which has improved by three runs. His slider has actually increased in run value since 2020, despite hitters overall hitting it less well.)

Now, saying that he’s located pitches similarly to last season is only partially true. Cease is a fly ball pitcher; his 42.6% fly ball rate is 16th in the league among starters with at least 100 innings pitched. Limiting walks and contact is in his best interest. The quality of contact allowed against Cease this season hasn’t changed a whole lot. But he has doubled down on his reputation for inducing fly balls on contact. Pitching higher in the zone leads to more fly balls, but it’s an effective place to live with the high-spin fastball and big-drop breaking pitches that Cease throws. The command of his fastball has improved and it shows in his ability to target the top edge of the strike zone. He’s throwing more strikes in the top of the zone rather than missing. Despite this, his 10.3% home run per fly ball rate is fourth lowest among all starting pitchers with a fly ball rate of at least 40%, behind Freddy Peralta, Cole Irvin and teammate Lance Lynn. His improved command has hitters swinging more both in and out of the zone. Opposing hitters have a 53.5% swing rate against his four-seamers, which is over five percentage points higher than last season.

In a game where it’s to the hitters’ advantage to hit the ball in the air, it seems like risky business to use this strategy. Hitters have an average launch angle of 17.8 degrees on batted balls against Cease this season, which is the eighth highest among starting pitchers in baseball. The White Sox pitching staff as a unit seems to utilize this strategy; Giolito (4th), Rodón (10th), and Lynn (15th) are all near the top in average launch angle. It’s working for them.

Armed with more effective pitches, Cease has been a solid starter for the White Sox all season long. Heading into the weekend, he’s tied with Aaron Nola for 14th among starting pitchers on the FanGraphs’ WAR Leaderboard. On Saturday, he’ll take the mound against the Yankees on the heels of yesterday’s Field of Dreams game. With Carlos Rodón reportedly having left shoulder fatigue, the White Sox will be relying on Cease even more down the stretch.