RADIO
Welcome back, RotoBallers, to my weekly "Starting Pitcher Arsenal Changes" article series for Week 16 of the 2024 fantasy baseball season. Today's article will discuss Andrew Heaney and DJ Herz. For those new to this column, each week, we cover a few starting pitchers and their arsenal changes via pitch mix, velocity, and movement. We're at a point where the pitch movement, arsenal, and velocity should tell us a story with several starts under their belts. With more injuries likely coming soon, we'll want to continue identifying streaming pitcher skills or struggling pitchers with underlying metrics suggesting better results coming soon.
We're halfway through the fantasy baseball season, nearing the All-Star break, causing fantasy managers to make crucial decisions for the second half of the season. With rookies like Herz, I tend to give them about a month to gather enough data to make actionable decisions. Meanwhile, we're looking at the successes or struggles of other starting pitchers to understand the why. Let's look through my process of examining starting pitchers and their arsenals.
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Andrew Heaney is Lowering the Four-Seam Usage
Against right-handed hitters, Heaney is throwing the fewest four-seamers (52.7 percent) in his career since introducing the pitch in 2020. That's about 6-7 percentage points below the four-seamer usage in previous seasons. Heaney traded fewer four-seamers for more sliders against right-handed hitters, as seen below.
The four-seam results against right-handed hitters have been decent, with a .294 wOBA, slightly better than this career wOBA (.335) against the four-seam. Heaney is an unusual pitcher who throws a four-seamer generating more horizontal movement than vertical or induced vertical break (IVB). That's mainly due to Heaney's horizontal release points.
Heaney uses a low vertical release point of about five feet. However, his horizontal release is around three feet away from the midline of his body. That indicates a lower three-quarters release point, which aligns with the additional horizontal movement on the four-seamer. Some left-handed starting pitchers with similar or more horizontal movement on their four-seamer include Nick Lodolo, Chris Sale, and Kyle Harrison.
Theoretically, pitches that have more horizontal movement should induce weaker contact. However, hitters can likely identify and attack the four-seamer with his arm slot since it lacks IVB. That's evident in Heaney's four-seamer locations and results. He often throws the four-seamer in the upper third of the zone, but hitters tend to crush the heater in those zones.
Interestingly, Heaney's four-seamer has been limiting home runs, with an 11.5 percent HR/F in 2024 compared to a career HR/F of 16.4 percent. Even his overall HR/F (10 percent) sits five percentage points below his career average, and fortune might be in his favor in 2024.
Heaney's Slider Swings and Misses Bounced Back
Heaney typically possessed the skills, but health has been the issue. However, it's worth noting Heaney's slider bounced back from a swing-and-miss standpoint. In 2023, Heaney's slider elicited a 14.4 percent swinging strike rate, which ballooned to 20.7 percent in 2024 compared to a career average of 20 percent. Why is that?
Over the past few seasons, Heaney's slider has been losing downward movement from 45.3 inches in 2021, 38.2 inches in 2022, 40.9 inches in 2023, and 41.4 inches in 2024. It's been slightly above-average vertical movement on the slider in 2024, supporting the bounce back in strikeout skill gains on the breaking ball.
Against right-handed hitters, Heaney's slider elicits a 22.2 percent swinging strike rate compared to 16.4 percent versus left-handed hitters. Heany commands and locates the slider down and inside the right-handed hitters 46.9 percent of the time, resulting in a .165 wOBA in Zone 13. When he hangs it slightly in the zone, right-handed hitters crush the slider with a .555 wOBA.
If a starting pitcher lacks an above-average fastball like Heaney, we want him to have an effective breaking or off-speed pitch. It's helpful if they possess both, but at least one gives us a little confidence.
Heaney's Changeup is the Wild Card
Heaney's changeup is the wild card because it could unlock another level if it generates more whiffs as a potential weapon against right-handed hitters (.242 wOBA, .292 xwOBA) and lefties (.443 wOBA, 154 xwOBA). The data is most actionable against right-handed hitters, throwing it 18.2 percent of the time compared to six times (2 percent) versus lefties in 2024.
In 2024, Heaney's changeup elicits a below-average 13.3 percent swinging strike rate, though hitters chase it 46.8 percent of the time. Heaney lowered the zone rate on the changeup by four percentage points while hitters chased the off-speed pitch over eight points above his career average. His changeup regularly garnered tons of arm-side horizontal movement, supporting the weaker contact in the expected stats. If hitters continue to chase at a higher rate, expect his swing-and-miss rates for the changeup to improve.
Summary
The story with Heaney revolves around his health (because the skills exist) since he only threw over 100 innings in two out of the previous six seasons (2018-2023). Heaney is on pace to surpass the 100-inning mark while coming off one of his better months in June. That's evident in Heaney's 3.41 ERA (3.53 xERA), 21 percent strikeout minus walk rate, and 13.7 percent swinging strike rate in June 2024. Heaney's slider and four-seamer have been performing and looking more like past seasons. However, we'll want to keep tabs on the changeup if it unlocks another level of strikeout upside for Heaney as a deep-league streamer.
DJ Herz Added Velocity
In Herz's start against the Mets, his four-seamer and changeup increased by 1 mph. The four-seam had nine or more whiffs for the third time in his rookie season. Eight of his nine four-seamer whiffs against the Mets came in the upper third of the zone. Herz bounced back after a scoreless six-inning, 13-strikeout performance against the Marlins, then two shortened starts of under four innings and six combined strikeouts.
It looked like Herz's slider jumped over 5 mph from his season-long average. However, it ended up being a pitch classification issue because it appears he threw the cutter 21.7 percent of the time on July 2. The movement profile matches the cutter with below-average vertical and horizontal movement. Regarding velocity, Herz's four-seamer and changeup might be the most notable because of the significant jumps in a recent outing. Though Herz struggled against the Cardinals on July 7, the velocity gains stuck around with the changeup.
Herz's four-seamer remained a weapon, with a 15.2 percent swinging strike rate against the Cardinals and a 13.7 percent overall. All of his four-seamer whiffs came in the upper half of the zone, though we would prefer more to be in the upper third. Again, Statcast might struggle with in-game pitch classification for Herz since his slider velocity and movement align more toward the cutter.
Herz Lowered the Four-Seam Usage in July
We might be nitpicking here because we're dealing with small samples. However, Herz threw his four-seamer at the lowest rates in July through seven starts. In five out of seven outings, Herz threw his changeup over 21 percent of the time. Meanwhile, Herz's cutter (or slider in Statcast game feeds) usage increased by over eight percentage points in July.
Herz's four-seamer rates are average to above average in IVB, with 15.9 inches of vertical movement and over 11 inches of arm-side horizontal movement. Theoretically, Herz's four-seamer should have better outcomes, as evidenced by his .278 xwOBA compared to a .362 actual wOBA. The four-seam worked well against lefties before his July 7 start, but the wOBA ballooned to .363. Nevertheless, he throws it mostly against right-handed hitters.
Herz's four-seamer elicits swings and misses, with a 14.1 percent swinging strike rate. The poor four-seam outcomes have been luck-related, too, given his .439 BABIP allowed. While it's not a high-end or near-elite four-seamer, Herz's fastball possesses decent metrics to use as his core pitch. However, it makes sense for him to lower the usage in his past two starts.
Should Herz Keep Throwing the Cutter More?
Before deciding whether Herz should throw the cutter more, let's examine the cutter's pitch movement profile. The cutter is more of a breaking ball, possessing over 31 inches of downward movement with about one inch of "cut" or horizontal movement. For context, Herz's cutter compares similarly to Bryan Hudson, Cole Irvin, Genesis Cabrera, and Ryan Yarbrough among left-handed pitchers.
Since Herz's cutter profile compares closely to Irvin's, the visual below shows where Herz would be if he qualified among left-handed pitchers.
The upside comp for lefty cutters would be Max Fried, but he only threw it 4-5 percent of the time over the past two seasons. Herz's cutter is unusual because it doesn't have as much downward movement as the slider, making us wonder about its purpose. In Herz's July 2 start, his cutter generated a 20 percent swinging strike rate, twice the season-long average of 9.7 percent. However, his cutter/slider elicited a 12.5 percent swinging strike rate in his start against the Cardinals.
If Herz's cutter can result in more swings and misses, it's logical for him to use it more often. However, the cutter movement profile doesn't give us confidence in him sustaining the whiffs unless hitters chase it outside the zone because it likely won't be effective in the zone.
Summary
Herz's results should be better, evidenced by his 3.80 xERA, 22 percent strikeout minus walk rate, 14 percent swinging strike rate, and 185 BaseballHQ BPX or base performance value. That indicates Herz possesses above-average skills, but the luck factors have been shifting away from his favor. It makes sense for Herz to lower his four-seamer usage since the pitch shape metrics look concerning, though he elicits swings and misses. Keep tabs on the cutter since he seems to be throwing it more often, with decent results in the small sample. Herz warrants deep league attention, but the road to success might be rocky.
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