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FS: Scouting Sergio Santos With Pitch F/X

Jason Gage

Accountant By Day, Sports Analyst By Night

Written by, Jeff Buchanan,

This year, for the first time, PITCHf/x was running for the Arizona Fall League. This gives us a wealth of data on what the pitchers in Arizona threw, from velocity to pitch locations, pitch movement etc. etc. and instead of having to rely on vague, second hand reports thrown at us from the likes of Phil Rogers, we can instead get an accurate and detailed look at each pitchers repertoire from the data provided.


Unfortunately the White Sox did not send many pitchers of interest to the Arizona Fall League, but one player who did catch the eye was Sergio Santos. Santos is a former 1st round pick, he was selected number 27 overall in the 2002 first year payer draft by the Arizona Diamondbacks, but after stalling as an offensive prospect the White Sox signed him and converted him to pitching. In his first season off the mound Santos had some fairly mixed results, including an 8.16 ERA and a 6.38 BB/9 in 28.2 innings over four levels. There were some encouraging points for Santos, namely his 9.57 K/9 and a purported 99 mph fastball. The White Sox recently added Santos to the 40-man roster protecting him from this years Rule 5 Draft, so they obviously see something that they like in Sergio, but let's see what PITCHf/x has to say.

Velocity Table:

Pitch Type Max Velo Min Velo Average Velo
Fastball 98.8 93.6 95.84
Slider 88.8 84.5 86.53
Change 87.3 82.2 85.36
Curve 87.2 82.9 85.2


As you can see from this velocity table Santos can dial it up. He didn't quite manage to hit the triple digits, but he was the second hardest thrower in the AFL, behind, guess who, Stephen Strasburg. The average fastball velocity from a right handed pitcher is around 92 mph, so Santos' average FB velocity of 95.68 mph gives him legitimate plus velocity. The differential between Santos' fastball and changeup velocities was just over 10%, which is very good. His fastball/slider differential was also solid.

Movement Graph
Raw Data:

Pitch Type Horizontal Movement Vertical Movement
Fastball -9.24 6.38
Slider 0.08 -0.39
Change -11.01 1.35
Curve 0.05 -6.47


First I'll give a brief explanation of the movement graph. We're looking at it from the catchers standpoint. You'll notice that the graph indicates some of the pitches are "rising", however, due to the laws of gravity we know this is not possible. What the graph is actually showing is how much each pitch moves compared to an otherwise similar pitch thrown withot any spin, so Santos' fastball is not actually rising by an average of 6.38 vertical inches, but instead it is falling 6.38 inches less than an otherwise similar pitch thrown without any spin. Likewise, negative vertical movement indicates the pitch fell by however many inches more than an otherwise similar pitch thrown without any spin. Negative horizontal movement indicates the pitch moved in on a right handed batter and positive horizontal movement indicates the pitch moved in on a left handed batter, again, compared to the otherwise similar pitch thrown without any spin.

Without context, this data means nothing, as we don't have any reference points to tell us whether Santos' movement is above or below average. So what I'm going to do is compare Santos' movement to the average moment of a right handed pitcher.

Average pitch movement from a RHP:

Pitch Type Horizontal Movement Vertical Movement
Fastball -5.1 8.5
Slider 2.2 2.2
Change -6.3 5.0
Curve 5.2 -4.8


From looking at this average movement data we can see that Santos' stuff moves... a lot. He's getting upwards of 2 inches of sink more than average, and anywhere from 2-5 inches of negative horizontal movement more than average. Now getting a lot of movement isn't necessarily going to be a good thing and it can lead to control issues, something that Santos has had. But if you can put the ball over the plate on a consistent basis while getting a lot of movement, I've got to assume that this will yield good results.

Release Point Graph

Next up I'm going to look at Santos' release point graph. This isn't especially useful from a diagnostic standpoint but it does allow us to see if a pitcher is tipping any of his pitches. You can see from the graph that his changeup is coming from an ever so slightly lower point than the other three pitches, but it's a negligible amount and Santos should be fine when it comes to tipping pitches.

Pitch Location Graph

Now we get onto Sergio's Achilles heel; control and command. You can see from the location graph that Sergio's pitches miss, often. You'll notice that both his fastballs and changeups are missing almost exclusively to the right side of the plate (from the pitchers perspective) and this is exactly what you would expect given what we saw on his movement graph. You'll also notice that his pitches are missing down often, and again this is to be expected given what we saw in the movement graph; if your pitches get a lot of sink, when you miss, you'll likely miss down and out of the zone. To this point we've seen that Sergio's velocity and movement have been significantly above average, but his control is certainly well below average. He will need to improve this if he wants to stick with the Sox out of ST.

Flight Path 1

Flight Path 2

The last graphs that I want to look at are of Sergio's flight paths. Flight paths, as you can probably imagine (and see), show the estimated path than an average pitch takes from release point to the catcher. They effectively tell you the same thing as the movement graph but it's a little more palpable for PITCHf/x newcomers. You can see that Sergio's slider has some good break to it and I like the pitch quite a lot, it also looks to take a very similar initial path to the fastball, which may make the pitch tough to pick up. Again you can see the extreme movement of the change, another pitch that could prove very valuable to Sergio if he learns to consistently throw it over the plate.

Pitch Type # Thrown Whiff Rate
Fastball 120 5.83%
Slider 33 36.36%
Change 42 21.43%
Curve 3 33.33%


Finally I'm going to try and summarize the effectiveness of each of Santos' pitches with the help of whiff rates. Whiff rates tell you how often a pitch incurs a swinging strike, or in other words, how difficult a pitch is to hit. The slider is the pitch that really jumps out for me and the 36.36% whiff rate is significantly above the league average whiff rate for a slider of 28.7%. For me, the slider is by far Santos' best offering, it has good movement, velocity and has been proven difficult to hit even in an extreme hitters environment. Santos' fastball has the makings of a great pitch with the plus velocity, but it has disappointingly low whiff rate of 5.83%. I think this is case in point of how velocity isn't everything. You need to have command of a pitch in order to utilize it's full potential. I think Santos' fastball at present is average at best, but with the potential to be much more than that. Like his fastball, Santos' changeup also has a below average whiff rate and the lack of control makes it a below average offering. The movement that Santos gets on the change could make it a neutralizing pitch against left handers but he must get it over the plate more consistently. Up to this point I have been including Santos' curve for tokens sake and due to the fact that he only threw three of them, I would not feel comfortable making any kind of evaluation of it.

So in conclusion, I see Sergio Santos as currently having a fringe average fastball, a plus slider and a below average change. All of his pitches should improve as (or if) he learns to better command them. Due to being out of options, Sergio will need to stick with the big club out of Spring Training or he will be exposed to waivers. It's probably too early for him to pitch in the Majors as he needs at least one more year to work on his control, but he could surprise, again in Arizona, and take the last spot on the roster.

All PITCHf/x data was taken from Brooks Baseball
Flight Paths were created using Harry Pavlidis' template file from BtB
Average pitch movement was taken from Harry Pavlidis at BtB
Average whiff rates by pitch type were taken from Sky at BtB

I'm a PITCHf/x newcomer so all constructive criticism is welcomed and encouraged.
PITCHf/x is not 100% accurate, I did not change any pitch classifications and as a result some of them are likely to be wrong.



The story was written by Jeff Buchanan, is SoxNet's sister site and is focused solely on the White Sox minor league prospects.



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JimH. said:

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Well that is really something. Quite an article. Good for you for putting it all together and posting it. I agree with your conclusions, this is a guy who will more than likely need more time to figure out command and control. To be frank he's a longshot but I always root for guys like this. Seeing as they saw enough to put him on the 40 man indicates he's got talent.

Jason Gage said:


I loved the article as well. Very interesting piece, more interestingly, I didn't realize how good Santos secondary stuff was.

We knew he had a live arm and a great fastball but having a nice slider is even better.

He clearly has things to work on and is a long-shot, but all it takes is to be right once in a great while on these gambles (position changes) and they can pay off huge.

Santos and Nathan Jones are clearly the two guys in the system most people would gloss over, but they are also two guys that if they put it all together, have the stuff to be shut-down relievers.

JimH. said:

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Speaking of Phil Rogers ...

Spoke to him recently, he hangs out at a place in the western suburbs that I also visit for drinks/dinner.

He mentioned one guy the White Sox were really really impressed with in Instructional League was a kid drafted from Auburn, Taylor Thompson, a right handed pitcher. They seem to think he's a diamond in the rough and could move fast. I think he was drafted almost as an afterthought, way low in the draft.

Dan Santaromita said:


I've seen this elsewhere as well. Thompson had a bad junior year (9 ERA) so he was expected to go back to school. I've seen him as having a 'power sinker.' I think that was from Baseball America, but I'm not sure.

Jason Gage said:


Very interesting stuff. I also vaguely recall hearing that the Sox were high on this Thompson kid.

I guess we'll see what he does over the next couple years in the majors. Nice to see he's got a power sinker as that would fit in nicely on the Southside.

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