Trevor Bauer and High Heat

Last weekend, as many may have noticed, Arizona Diamondback prospect Trevor Bauer was engaging his twitter followers in regards to fastballs both in the upper and lower part of the zone. Well, to be more accurate, he was suggesting that the fascination with throwing your fastball down in the zone was overrated and generally just wrong. It all began with this:


Bauer went on to engage his followers in a long discussion about the issue, so you can check out his timeline for March 25th if you want to see all of his thoughts on the issue. However, since run values on pitch locations are a subject that interest us, we decided to look into the matter a bit futher. So, Trevor, this post is for you.

Jeff Zimmerman, who is the person you can really thank for this, ran the numbers and came up with what you will see below. He looked at the Arizona Diamondbacks rotation and the league average rates for balls in the lower part of the zone and upper part of the zone, as well as two guys that initially popped into my head as pitchers who throw fastballs up in the zone – Jered Weaver and Brandon Beachy.

 FB High in Zone % of Pitches in Top of Zone AVG for Balls in Play Bases Per Hit Bases per Batted Ball Swing and Miss
Collmenter 59.3% 0.300 1.82 0.55 5.1%
Kennedy 50.7% 0.305 1.71 0.52 14.1%
Hudson 42.9% 0.283 1.59 0.45 17.1%
Cahill 49.3% 0.324 1.73 0.56 5.9%
Saunders 47.4% 0.334 1.63 0.55 6.9%
Weaver 60.9% 0.304 1.84 0.56 10.1%
Beachy 51.9% 0.277 1.65 0.46 15.0%
League Avg 57.0% 0.336 1.67 0.56 12.2%


FB Low In Zone AVG for Balls in Play Bases Per Hit Bases per Batted Ball Swing and Miss
Collmenter 0.301 1.45 0.44 10.2%
Kennedy 0.360 1.65 0.59 5.7%
Hudson 0.360 1.50 0.54 6.3%
Cahill 0.337 1.88 0.63 8.6%
Saunders 0.351 1.60 0.56 5.6%
Weaver 0.363 1.59 0.58 6.9%
Beachy 0.458 1.64 0.75 5.1%
League Avg 0.358 1.54 0.55 8.7%


What we can basically take from these numbers is that batters have a better chance at an extra base hit with a fastball up in the zone rather than down in the zone. Bauer stated that he “bet more of those jacks came on fastballs in the lower half of the zone than came on fastballs in the upper half.” What these numbers show is that more bases per hit come when fastballs are in the upper portion of the zone, while bases per ball in play are more-or-less equal. So, if a pitcher consistently throws fastball up in the zone, he is more likely to create more outs but also allow more extra base hits. There is a decent trade off there, and this data could be useful for certain in game situations. For instance, with a big lead, it may be worthwhile to throw fastballs up in the zone to create outs more often despite the likelihood of allowing an extra base hit.

Swing and miss rates also favor fastballs in the upper portion of the zone. The league average of 12.2% swing and misses in the upper portion easily trumps the 8.7% rate on fastballs in the lower half. This goes in line with traditional thinking, as higher fastballs are generally thought to be more difficult to catch up to.

Bauer also specifically mentioned how “Colly,” which we assume means Josh Collmenter, pitches in the upper half of the zone and has “great success,” as he put it. For reference, we looked at Collmenter’s results with all of his pitches in the upper and lower parts of the zone as well as the results of his fastball.

Collmenter All Pitches % of Pitches in Top of Zone AVG for Balls in Play Bases Per Hit Bases per Batted Ball Swing and Miss
Top Zone 50.8% 0.307 1.73 0.53 12.3%
Bottom Zone 49.2% 0.306 1.47 0.46 14.6%


Collmenter FB % of Pitches in Top of Zone AVG for Balls in Play Bases Per Hit Bases per Batted Ball Swing and Miss
Top Zone 59% 0.300 1.82 0.55 5.1%
Bottom Zone 41% 0.301 1.45 0.44 10.2%

Collmenter did see above average success last year in terms of bases per batted ball in the upper half of the zone, but he also saw similar success in regards to pitches in the lower half of the zone. His swing and miss rates for both halves of the zone were slightly better than average, so it is difficult to say that Collmenter sees “great success” in the upper half of the zone specifically. Looking at his fastball specifically, which he threw with 68% of his pitches last year and kept in the upper portion of the zone 59.3% of the time, he actually performed better in the lower part of the zone. With a BABIP and bases per hit average much lower than league average in the lower portion of the zone compared to average or worse than average marks in the upper portion, you can actually say he saw more success with his fastball in the lower portion.

What Collmenter did do is create outs without receiving ground balls, which likely caused Bauer to have the opinion that he sees great success up in the zone. He was certainly accurate in stating that he does throw up in the zone regularly, as he throws more than 50% of his pitches in the upper half yet still posted a better than average home run per fly ball rate of 7.7%.

There is also a decent chance that Collmenter was simply fortunate with balls in play. His overall .255 BABIP indicates that this is a possibility. For a pitcher with a 47% fly ball rate, he certainly did receive favorable results. It will be interesting to monitor Collmenter’s zone tendencies along with his home run per fly ball rate and BABIP this season. Maybe there is something to Collmenter’s pitching style, but it could also have just been a season filled with some good fortune.

Bauer stood by his opinion that balls are not necessarily harder hit up in the zone compared to lower in the zone throughout the debate. While it is possible that the balls are not physically hit harder, the likelihood for them to end up in places where the hitter can gain extra bases does increase. Bauer seemed extremely confident in his position, and by the sound of it he was basing it off of data – which would be very interesting to see if this were the case. The numbers ran by Jeff do not necessarily debunk his theory, but they do explain that more hits come from balls in the lower part of the zone and more extra bases come from balls up in the zone, which certainly does not help Bauer’s argument. We will most certainly follow Bauer’s numbers in this regard throughout the season, once he reaches the Majors, and also throughout his career.

Ben has been at RotoGraphs since 2012 and focuses most of his fantasy baseball attention toward dynasty and keeper leagues.

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12 years ago

Great work Ben and Jeff. Really good stuff. I’m wondering if this changes with the type of fastball that’s thrown, though analyzing that might be much better served with incorporating some kind of Pitch F/X. Collmenter in particular does throw a cutter that might be more effective for him up in the zone, whereas his 4-seamer probably fits in well with this analysis.