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What’s up with Seranthony Dominguez?

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Are his issues this season diagnosable?

Minnesota Twins v Philadelphia Phillies Photo by Mitchell Leff/Getty Images

Well, you can’t really be all that surprised, I guess.

Seranthony Dominguez’s rise last year was one that no one really saw coming. He went from being in Reading for a few innings to a brief pit stop in Lehigh Valley before he came the Philadelphia to stay. That kind of meteoric rise from an unheralded arm isn’t something you see quite often. Even though he dominated in such spectacular fashion early on in 2018, it just always sat in the back of our minds that maybe it was too good to be true, that these things really don’t happen too often. Unfortunately this year, we are finding out that that is correct.

Dominguez might be the most disappointing player on the team right now. Coming into the season, his peripherals in 2018 led projection systems to think he might be in for another dominant year. That dominance just hasn’t developed yet. The peripheral numbers are all still there - strikeout rate, walk rate, velocity - it’s all still in the upper echelon of relievers. He just can’t seem to get the same results as last year.

You can almost pinpoint the exact moment that it began to crumble last year too. Look at these arbitrary endpoints and how Dominguez was performing.

S. Dominguez in 2018

Date IP ERA HR K% BB%
Date IP ERA HR K% BB%
5/7-8/3/2018 39.0 1.85 1 34.0% 8.5%
8/5-9/30/2018 19.0 5.21 3 28.2% 11.5%

It was right around the 5th or 6th of August that Dominguez began to take a dive in his season numbers. Why is the 5th important? It was when this happened. The next day, Gabe Kapler decided to put Dominguez right back up on that horse and try him again in a pressure situation and guess what!

This is when the downhill crumbling of Dominguez began. Even the thinking that he “went downhill” is relative since his final numbers during the last two months are really affected by three bad outings. But it is difficult to truly trust him these days since, using the eye test, he just looks different. He seems more hittable, even with the filthy arsenal still at his disposal. So, what’s going on? Let’s take a deeper look to see if we can find anything. We’ll do that by asking two major questions that usually leads to sudden bouts of ineffectiveness, followed by the most obvious one that cannot be answered by numbers.

Is his stuff different?

When looking at his stuff, we often think of it in terms of velocity. If he’s throwing the ball slower, naturally hitters will get a better look at it. Remember, these are major league hitters and even a difference of a mile an hour or two can drastically alter how well hitters are hitting him. Here we have our first tiny bit of evidence.

In the early going, most everything is a tick slower than last year velocity wise. On average, he’s down about one mile an hour on his fastball and a fraction slower on his slider. On the plus side, judging from his month to month numbers, he’s trending upwards toward where he was last season. We can also look at his movement on his pitches, both vertically and horizontally and find that there is a bit more of a difference in the break of these pitches (I’m asking you to click on them to save your eyes from the amount of graphs on his page.) Is that the main cause of his issues? Are his pitches moving more and coming in slower, leading to a difference in results? I just don’t see too much of a difference to be concerned about.

We can also look at his stuff to see how the hitters are doing against him. It seems that his fastball is being dinged a bit more this year than in the past, but that isn’t too much of a jump to explain everything. It’s possible that the team has noticed this as well since we can see a big jump in how often he uses the fastball as compared with how often he uses his slider.

You see that big jump in the slider usage this year since they have identified it as his best pitch and are probably encouraging him to use it more often. This is a coaching staff that isn’t afraid to have a pitcher use his best pitch as often as he needs, regardless of whether it is a breaking pitch or a straight fastball. So, does this give us a definitive answer? I’m not sure, so let’s move on to the next part: pitch tipping.

Is he tipping pitches?

This one requires a different way of looking at things. We have to look at the possibility that his delivery might be different, or that he is releasing his pitches in different spots than his previous weeks of dominance. Let’s first look at release point.

He’s coming in, on average, from about two tenths of a inch lower than he was last year across the board. Had he only been doing it with one pitch, that might be the issue, but as you can see, the lines showing his release point move along the graph almost in unison. If he is tipping using release point, then those hitters are a lot sharper than we give them credit for. So, let’s look at some of his actual pitches to see if there is something different about his delivery when he throws a slider and a fastball.

Let’s begin with the thought that pitches are usually tipped prior to delivery. It would be extremely difficult to be able to discern what is coming, react and drive a ball with authority as a ball is being delivered unless it is that obvious that a batter can do it. So, we’ll look for something out of the setup to see if we can see anything.

This is how Dominguez was setting up to throw a fastball. Notice where he holds his hands. In the first image, from 2018, his hands are up near his ears while in the second image, from 2019, his hands are well below his chin. There is a big difference in where the hands are located, but that doesn’t really tell us too much. Let’s look at the slider, his other primary pitch.

Again, the hands are a lot lower in 2019 than they are in 2018. That doesn’t really tell us much, but what I want you to notice is to make the images from the fastball and slider match years.

See much of a difference?

Me either.

There doesn’t seem to be any evidence that he is tipping pitches because his setup on both pitches in both years looks to be identical to each other. I can pretty confidently tell you that it remained that way through most of the hundreds of pitches I looked at for this piece. While there was some slight changes in hand placement, the general consensus was that this year, his hands are lower than 2018, but they aren’t different from pitch to pitch. While we don’t have the insight and video that the players do, it doesn’t look like he’s tipping pitches either.

Is he hurt?

This is the one we just don’t know. There isn’t a quantifiable way of answering this question outside of straight up assuming he is. We don’t want to make assumptions either, since that leads to a bad place in analysis. However, judging from the amount of times Kapler has used him thus far this season, it is highly doubtful that an injury has occurred. I don’t think the team would be foolish enough to where they would put someone of Dominguez’s skill at risk so early in the season when they have reinforcements at the ready in Lehigh Valley.

So, what exactly is the issue with Dominguez? I think we can just chalk it up plain old bad luck. When looking at his advanced numbers, you see a 3.05 FIP for the season, a difference of 1.65 when compared to his 4.70 ERA (through Sunday). His walk rate his down, his strikeout rate is slightly down, but his hits per nine is doubled from last season. That leads us to the likely culprit: BABIP.

BABIP in 2018: .220
BABIP in 2019: .375 (!)

There you go. All of that analysis and we can probably trace this back to bad luck. He’s been sacrificed to the BABIP gods. It happens, especially to relievers. They’re prone to variations in these kinds of numbers, which skew their scoreboard numbers and make them look like they are having a worse season than they actually are. This leads me to believe that when the middle of July and August hits and we look back at this stretch, we’ll find that it was merely a bump in the road of a young pitcher’s development. We won’t know until then, but as of now, I wouldn’t be too concerned about Dominguez. Let’s keep an eye on him and see how the rest of the season progresses.