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Know your Astros Relievers: The Prospects, Part I

Continuing DQ's solid work on Bud Norris, I thought we could continue with a few profiles on the Astros top reliever prospects, Samuel Gervacio, Danny Meszaros and Chia-jen Lo.

Gervacio made the big leagues last season, pitching 29 games in front of Pitch f/x's cameras. As for Meszaros and Lo, they pitched in the Arizona Fall League this November and two of the ballparks there have Pitch f/x cameras, including the Peoria Saguaros' home park.A few of their appearances did get left out of the data, but we've got a good chunk to work with.

First up in our analysis is Gervacio. Thanks to a wonderful website, I was able to pull all the season's data for Gervacio, complete with charts and graphs, which will follow after the jump.

Sadly, none of these relievers have a ton of data to look at, since none of them pitched in front of tracking cameras very often. Gervacio leads the way with 21 innings and 331 pitches. Nearly half the pitches he threw last season in the majors were sliders while also sporting a two-seam and a four-seam fastball. Gervacio did try to throw a curveball and a changeup, but as the chart below illustrates, those cases were few and far between.

Type Count Selection Velocity (mph) Vertical (in) Horizontal (in)
Slider 153 48.7% 85.0 0.04 1.39
Four-Seam 81 25.8% 91.0 2.21 -8.26
Two-Seam 63 20.1% 91.2 1.50 -9.44
Changeup 14 4.5% 83.3 0.49 -9.25
Curve 3 1.0% 84.5 -3.25 3.94


Interestingly enough, both his fastballs break back in on a pitchers' hands. The two-seamer has more horizontal motion to the left side of the plate and about three-quarters of an inch drop in vertical movement over the four-seamer. Both were thrown about as hard, though I would bet given a seasons' worth of data, this would become more pronounced and the horizontal and vertical movements less so.

His slider is the pitch he uses the most and it works a little like a changeup, with a 5-6 MPH difference between it and the fastballs. With the slider, Gervacio pounds the outside of the plate. Here's a look at the average path his slider took to home plate.

Top View of Average Slider


Side View of Average Slider


Two things really jumped out at me from these two graphs. First, his slider seems to really start diving down about 25 feet from home plate. Before that, it's trajectory very well could make it look like a fastball, thus making it a little deceptive. Secondly, with the kind of outside break he's getting it's obvious he isn't throwing this to left-handed hitters too often. Let's look at the top-views broken down by splits:

Top View of Average Slider to RHB


Top View of Average Slider to LHB


With such a pronounced break towards the left side of the plate, you would expect Gervacio to throw the pitch more sparingly to left-handed batters. Indeed, he used the slider only 26 times against lefties, relying instead on his two-seam fastball most often and mixing in 10 of his 14 changeups. Granted, we're dealing with an even smaller sample size, since he only threw 91 of his 331 pitches to lefties. His splits bear this difference out too, as Gervacio struck out just four lefties out of his 25 total strikeouts. He also walked five lefties in just 26 plate appearances. However, his two-seamer was effective enough to limit his BABiP to .267 for lefties and generate two of the three double-plays he induced.

You can see, though, by these two scatter charts that Gervacio is clearly more comfortable throwing his slider for a strike and this may have contributed to those numbers.

Strike Zone to RHB


Strike Zone to LHB


Gervacio was very, very reluctant to come inside on lefties, while he successfully utilized both sides of the plate against righties. He still had a cluster of sliders low and away to RHB, but that's where he wants that particular pitch. As I said, this may be due more to random noise than to an actual trend, but it definitely looks like Gervacio needs to work on his control pitching to LHB.

Another way of looking at this is his strike percentages on his splits. Here is the chart for both RHB and LHB:

To Righties:

Type Strike Swing Whiff
Slider 69.3% 44.9% 18.1%
Four-Seam 61.8% 52.7% 20.0%
Two-Seam 54.3% 28.6% 11.4%


To Lefties:

Type Strike Swing Whiff
Two-Seam 53.6% 39.3% 3.6%
Slider 65.4% 50.0% 19.2%
Four-Seam 53.8% 30.8% 3.8%


While he gets more swings at the slider from LHB, he doesn't quite throw it as consistently as he does to RHB. The big thing that jumps out here is how inaccurate his four-seamer got to LHB and how few swing-throughs he got. More contact led to more grounders and the like, but still...that's not going to make him luck-friendly in the future if this trend continues.

So, now that we've looked in depth about his splits, it's time to delve into his other two favorite pitches, the four-seam and two-seam fastball. Let's look at a top and side view for each pitch first:

Four-Seam from Top


Four-Seam from Side


Two-Seam from Top


Two-Seam from Side


See how similar they look for the most part? From the side, the two pitches are almost identical with the slider Gervacio throws. Just to illustrate the point, here's a grouping of all the average paths for his pitches from the side.

Side View


Notice its' not until about 15 feet that the slider starts dropping away from the other two. Before that, all three pitches are very close in downward plane, making it more critical for the batter to pick up the spin of the ball to determine what pitch is coming at him. Instead of a drop in the three pitches, the biggest difference is obviously horizontal movement. As I said, there's really not a lot of data to support whether the large (and relatively late) movement of his two fastballs is indicative of his true talent or just a small sample, it does help explain a little of his wildness issues to lefties.

Gervacio probably needs to work on his control a little before he wins a spot in the big league bullpen, as I could see a more crafty manager exploiting his problem throwing to LHB in crucial situations late in games. However, his slider looks like a great pitch and projects nicely to the back end of the Astros bullpen in the future.