The Zack Wheeler Testimony
If you have been following my twitter account for the past few weeks you would have noticed the uptick in the number of tweets relating to Zack Wheeler — specifically the number of tweets relating to Zack Wheeler’s intrigue to a team like the Dodgers (or any forward thinking team for that matter). Well, I’ve come to the determination that I simply can’t get my entire rationale for why Wheeler would be such a good fit on the Dodgers across on twitter, and that as a result of that I’m forced to bore you with another Medium post. I’ll cut right to the chase, and get to why I think Wheeler should be the top pitching (and possibly overall) target for the Dodgers this winter.
Optimizing Wheeler’s repertoire
Before I get into things, I should clarify that I’ll be primarily using Baseball Savant for data on Wheeler’s repertoire. Why is this important? Well, Savant is different from FanGraphs and Brooks because they don’t classify Wheeler’s fastball as only a four seam — they have him throwing both a traditional four seam and a sinker (it’s also labeled as a two seam on their site, but the difference between the two names is pretty much just semantics ).
Okay, so what does Wheeler’s current repertoire look like?
So, as you can see Wheeler is a five pitch pitcher currently. He throws a “fastball” ~ 60% of the time, a slider ~ 20% of the time, a changeup ~ 10% of the time, and a curve 10% of the time. He also definitely does throw a split (he’s made it clear that it’s a different pitch than his changeup in an interview with the Athletic), but not enough of the time for me to really consider it a part of his repertoire.
Okay, now that we have established what kind of pitches Wheeler throws, now let’s look at what kind of results he gets when he throws these pitches.
wOBA against (via Baseball Savant)
Before we dig into the numbers, it would probably be beneficial to know that league average wOBA against for pitchers in 2019 was .324. Wheeler’s pitches look pretty damn good compared to league average besides his sinker — the one glaring weakness of his repertoire as its currently constructed. Really, the fix here is pretty obvious. Have Wheeler scrap the sinker, and replace them with more curveballs (not dissimilar to what Houston did with Gerrit Cole, but I’ll get more into that later). Let’s take a look at Wheeler’s sinker for a minute. It averages 2256 RPM, 15.9 inches of drop, and 13.9 inches of break. I’ll be blunt; those numbers aren’t good. The spin isn’t horrible ranking in the 68th percentile, but the movement numbers are particularly bad. His vertical movement (the amount of drop) ranks in the 2nd percentile and the horizontal movement (the amount of break) ranks in the 40th percentile. So the results have been really bad, and the pitch itself doesn’t seem to move well. Let’s compare the movement numbers on his sinker to the movement numbers on his Four Seamer: 2341 RPM, 13.1 inches of drop (lower is better here as less drop means more rise, which is what makes a four seamer more of a swing and miss offering), and 10.5 inches of break. His spin rate is good on the four seamer too; it’s in the 68th percentile. His four seamer ranks in the 88th percentile in terms of vertical movement and the 82nd percentile in terms of horizontal movement. In other words, his four seamer gets good results and it moves positively. Here’s an example of the difference between his four seam and his sinker:
The first GIF is a sinker thrown at 94.7 mph and has a spin rate of 2160 RPM. The second GIF is a four seamer thrown at 96.1 mph and has a spin rate of 2415 RPM. Even though the first sinker is still a pretty good pitch in on the batter’s hands, the difference between the two pitches epitomizes everything wrong with how much he throws the sinker. The sinker is slower and has less spin. His four seamer has an additional 255 RPM which is absolutely huge for the purpose of the pitch — getting swings and misses up in the zone. More spin on a four seamer gives the pitcher more wiggle room with regards to the importance of having a high spin efficiency. Spin efficiency is just the quotient of the transverse spin (spin pertaining to actual movement) and the total spin. If a pitcher has a spin efficiency of 100% on their fastball, that means all of the spin on their fastball is actually making the ball move. A high spin efficiency tends to lead to a greater magnus effect on the baseball. A greater magnus effect means the ball “rises” (the ball doesn’t really rise, but it appears to rise to the hitter) more than a pitch more than a pitch with a lower spin efficiency. Now how does this relate to Wheeler and spin rate? Well, having a higher spin rate allows a pitcher to still throw a fastball that undergoes a significant magnus effect even when their spin efficiency isn’t incredibly high. I’ll provide an example below of what I’m talking about. Pitcher B, has a higher spin efficiency than pitcher A, but pitcher A is still getting more useful spin (transverse/true spin) than pitcher B because he has a higher starting point (total spin).
My point being: Wheeler should throw the pitch with the higher total spin rate because it is likely going to give him the offering that is undergoing the magnus effect to the greatest extent. So, I think it’s safe to say we’ve come to the conclusion that Wheeler should throw his sinker much less.
Now that we’ve established what pitch Wheeler should drop, we have to identify what he should throw more of to replace the sinker usage. Looking at the results he’s gotten with his pitches, and some of the other characteristics I’ll get into later, I think he would be best served throwing his curveball more often. Wheeler throws a true 12-to-6 curveball. It averages 2647 RPM (72nd percentile) and 54.1 inches of drop (67th percentile). What’s most interesting to me about his curveball is how it plays off his fastball. Spin mirroring is how a pitcher is able to — in essence — mirror the spin axis of two different pitches, making it harder for the hitter to identify which pitch is being thrown. Spin mirroring is important when pairing fastballs and breaking balls. Ideally, the closer to 180 degrees the better when it comes to mirroring; 180 degrees is a perfect mirror. Wheeler’s spin difference between the spin axis on his FB and CB is 189 degrees. Not quite 180, but actually a bit over it which makes some sense considering his CB has a ton of topspin, and his FB is more of a side spinner than a true backspin type (e.g. Kershaw’s fastball). His fastball spin axis is 221 degrees and his CB spin axis is 32 degrees. To put this into context: the closer a FB spin axis is to 180 degrees, the more backspin or rise the FB is going to have. And on the other end of the spectrum, the closer to 0 degrees a CB is the more topspin or drop the CB is going to have. My general ideology is to characterize any fastball between 180 and 210 degrees as a backspinning fastball, and any curveball between 0 and 40 degrees as a top-spinning curveball. The point I’m trying to make is: Wheeler has a really freaking good curveball that has a huge spin difference with his fastball, which might make the two play really well together with an increase in usage. Here’s an example of his big curveball:
Gerrit Cole 2.0?
This kind of started off as a meme on my end, but the more I dug into Cole pre-Astros the more I started to be surprised at the number of similarities he has with Wheeler. Before getting into their pitch mixes, lets take a look at Cole’s numbers from 2015–17 (When he first really established himself as a good MLB starter) and compare them to Wheeler’s numbers from 2018–19 (When he established himself as a good MLB starter)
They’re pretty much identical across the board. If anything, Wheeler has an advantage in the two stats I weigh the heaviest when I look at pitchers: DRA and pCRA. Obviously Cole is no longer the same pitcher, but it’s interesting to look at where he was before he got moved to a more progressive organization.
Cole’s pitch mix was eerily similar to Wheeler’s too. In 2017 Cole threw a four seamer, a sinker, a slider, a curveball, and a changeup. Cole’s four seamer and sinker both got hit really hard (.347 and .328 wOBAs respectively), but all his off-speed pitches were pretty effective. He only threw his curve 12% of the time in 2017 compared to his sinker which he threw 13% of the time. Once he got traded to Houston, Cole’s sinker usage went to 6% and his curveball usage went to 19%. So really, what I’m hoping the Dodgers do with Wheeler is mirror what Houston did with Cole. Drop an ineffective pitch (sinker), and replace it with a higher frequency of a more effective pitch (curveballs in this case).
There might be a little more we can gleam from Cole’s transition to Houston though. In Pittsburgh Cole’s FB spin axis was 222 degrees, practically the exact same axis as Wheeler’s in New York. Once he got traded to Houston, Cole’s spin axis dropped pretty dramatically going from 222 to 215 degrees. While that might not seem significant, a change of just 7 degrees can alter a lot of the pitch’s characteristics (i.e. spin rate, vertical & horizontal movement, etc.). In 2017 Cole’s FB averaged 2164 RPM and 8.65 inches of vertical movement (using Brooks’ data). In 2018, after the trade, Cole’s FB averaged 2379 RPM and 9.87 inches of vertical movement. Both of those changes are pretty significant. By altering his spin axis slightly, and getting more backspin (remember, closer to 180 degrees is more backspin) his spin rate increased by over 200 RPM and he gained over an inch of rise. Now, could there be other factors that led to those changes? Of course, but it’s interesting nonetheless that a significant change in spin axis was accompanied by an uptick in spin rate and a rise in vertical movement. I think it’s not out of the question that something similar could be done with Wheeler’s four seamer. As you can see in the GIF of it above, his four seamer has the capability to get to over 2400 RPM, and it already rises a good deal; imagine if he made an effort to try to get more backspin on a consistent basis like Cole did in Houston? His FB has the potential to become one of the most dominant pitches in baseball.
The Need for More Velocity
Now that I’ve gotten all my reasons why I think Wheeler has the upside to get even better out of the way it’s time to go into a bit more detail as to why I think it’s important that the Dodgers sign him.
Velocity is king in October as Dodger fans are learning watching Scherzer and Strasburg mow down hitters one after another. The average wOBA in the playoffs is .322. The average wOBA on fastballs greater than or equal to 95 mph is .304. I don’t think it should come as a surprise to anyone that velocity plays in the postseason (I mean Nate Eovaldi shut the Dodgers down last postseason, and his FB is pretty meh in terms of movement). On the other hand, the average wOBA on fastballs less than or equal to 93 mph is .324. So if you sit 93 or lower you’re already at a disadvantage. How does this relate to the Dodgers? Well, let’s look at their postseason rotation in terms of average velocity. Buehler averaged 96.5 mph, Ryu averaged 90.7 mph, Kershaw averaged 90.3 mph, and Hill averaged 90.3 mph. So every starter not named Buehler was entering the postseason at a disadvantage; their velocity doesn’t give them much wiggle room. I think you can comfortably project Dustin May to join the rotation next year which should give them a second 95+ mph starter, but how reliable is a rookie Dustin May going to be? Wheeler’s fastball averaged 96.8 mph which would give them a third starter over 95 mph in the 2020 postseason rotation. I don’t think this should be the main reasoning behind them signing Wheeler, but I think it’s something that shouldn’t be overlooked. We need more velocity.
ROI
The last thing I’m going to touch on is return on investment. Dodger fans are going to call for Friedman to go and give Gerrit Cole $200m, and rightfully so, he’s an unbelievable pitcher. My only problem with giving Cole $200m is you’re paying for his peak value — it’s not a huge problem obviously considering how good his peak value is, but it’s something that should be taken into consideration. With Wheeler, his market is going be significantly less robust, and I think it’s safe to project him getting around the same AAV as Ryu (in the $17–20m range). The difference with Wheeler is that you aren’t paying for his peak value, you’re paying for a good pitcher who has shown the ability to be even more than that. If you lend any credence in WAR’s monetary valuation (1 win is worth $8m), Wheeler was worth ~ $38m this past season. Now, there is no way he’s going to come close to getting that amount in free agency, but my point is I feel confident he is going to provide a significant return on the Dodgers’ investment. I think he can get to the level of being a 6 win pitcher, and at that point he’s going to be worth nearly $50m a year. So I think it’s a relatively safe bet that Wheeler is going to provide better value than Cole in terms of ROI. If you think Cole gets an AAV north of $30/year, he’s going to have to pitch like a 6 win pitcher during the lifespan of that contract to provide a comparable ROI to Wheeler’s deal (this is assuming Wheeler doesn’t improve, remains a 4 win pitcher, and gets a deal in the $17–20m range). If you buy Wheeler’s breakout upside (I do), the probability that he provides a greater ROI than Cole is pretty decent.
