Marcus Stroman under the Microscope

Image via Elise Amendola/Associated Press
(http://www.cbc.ca/sports-content/baseball/mlb/game/1378509/recap/)

[I’d be a horrible person and a worse writer if I didn’t first mention that on Friday, Jeff Sullivan of FanGraphs.com wrote an extremely similar article. I was already finished the research and well into the writing by that time, and considering that some of the numbers we each used are different and resulted in varying conclusions, I feel like this post is still worth sharing. If some reason you desire proof, here’s a Tweet I sent him on Thursday morning asking how he calculated the comp ratings. Please give his a read too if you haven’t yet had the chance.]

A little over a year ago, my first piece of writing made its debut on DrunkJaysFans.com. Aptly titled “Aaron Sanchez through the Lens of Pitch F/X”, the article used the data gathered during his brief Arizona Fall Leaguestint to find major league comparisons for each of his three pitches – his fastball, curveball, and changeup. Despite hindsight showing my methodology was admittedly primitive and based more around approximation than definition (not to mention extraordinarily small samples sizes), overall the piece was very well received. I proposed a follow-up for a later date in which I would analyze the other number one prospect in the system, but unfortunately the lack of data pitch data attached to Marcus Stroman’s name at the time made the offer an impossibility.

Thirteen months later, that promise is finally being fulfilled. Using Pitch F/X data from the Baseball Prospectus leaderboards, this article will offer the best major league comparable(s) for each of Marcus Stroman’s six pitches, using accurate statistical methods, no less. For each pitch, the population sample is right handed starting pitchers who threw it at least 100 times during the 2014 season.

The pitchers were measured based on three variables: velocity, horizontal movement, and vertical movement. Using Marcus Stroman’s values for each pitch as the control, the comparator pitches were had their Z-score measured. The Z-score allows us to calculate “the probability of a score occurring within a normal distribution” as well as, perhaps more importantly for this endeavour, “compare two scores that are from different normal distributions”. For example, the velocity formula used is as follows:

Z-score = ABS (pitcher velocity – Stroman velocity) / velocity Std. Dev. of the population

The absolute value toggle is important as if Marcus Stroman throws his fastball at 93 miles per hour, we want pitchers who throw 92 and 94 to receive the same score as they’re both equidistant from the value we’re using as the benchmark. The above calculation was done in identical fashion for both horizontal movement and vertical movement, resulting in three Z-scores for each pitch. The Z-scores are unit-less so they can be summed to create, as Jeff Sullivan of FanGraphs describes, a single “Comp Rating” for the pitch. The closer to zero the rating is, the more similar the pitches are to one another.

One final, important disclaimer: the pitches are being compared based upon their physical characteristics, not necessarily their effectiveness. For interests’ sake, however, I added the whiff/swing percentage and groundball/ball in play rates to the top five pitches as identified by the comp rating.

Four Seam Fastball:

One hundred and fifty-four right handed starting pitchers threw at least 100 four seam fastballs, with Stroman’s average velocity ranking at a well above average 35th. Twelve pitchers had a comp score within 1.00, which is unsurprising as four seam fastballs are the most common pitch type and there’s really not a ton of possible variation in shape outside of the highly exotic arm slots. As the table above indicates, velocity appears to be the most important corollary factor, as all of the top five comparable pitchers had an average velocity within half of a mile per hour of Stroman. In terms of physical traits, Cincinnati Reds ace Johnny Cueto comes out on top as the most comparable four seam fastball. However, when taking into account outcomes — and as mentioned, whiff/swing and groundballs per ball in play rates have been added as two key figures — Milwaukee Brewers rookie Jimmy Nelson may be the best comparison overall.

Sinker:

Touched upon in my previous Stroman article but worth noting a second time, Jeff Sullivan of FanGraphs identified a rapidly increasing number of sinkers thrown by Stroman on a month by month basis in 2014, and when analyzed versus sinkers thrown between 2008 and 2014, the sinker belong to Blue Jays legend Roy Halladay came out as the best comparison.

For the purpose of this article, only pitches thrown in 2014 were used for comparison, which obviously removes the retired Halladay from the population sample. Including Stroman, one hundred and twenty-one right handed starting pitchers threw at least 100 sinkers last season. The comp scores are notably weaker than those to Stroman’s four seam fastball with only one pitcher, Jacob Turner of the Cubs, coming in below the 1.00 mark. It’s certainly an interesting concept, as the 6-foot-5 Turner stands a solid eight inches taller than the Blue Jays pitcher. Despite this theoretical advantage, as the sinker heat maps below indicate, the shorter Stroman has nearly been Turner’s equal in terms of pounding down, and in terms of ground balls per balls in play, he’s actually bested the former ninth overall pick despite only picking up the pitch last summer.

Cutter:

The third and final hard type pitch Stroman throws is the cutter, and once again the Reds’ Cueto appears as one of the better comparables. The movement on Cueto’s cutter is incredibly similar to that of Stroman’s — not to mention the whiffs per swing; the leading cause of the gap in comp score is due to velocity as Stroman throws his nearly two miles per hour harder. The best fit belongs to current Mets closer Jenrry Mejia (who remains eligible due to his seven early season starts), and is due in large part to the similarity in velocity. Fifty-four right handed starters threw a minimum of 100 cutters, with Mejia and Stroman ranking 4th and 6th in terms of average velocity, respectively. Stroman’s 64% GB/BIP ranked 1st among cutters with Mejia’s 58% ranking 3rd, so the comparison appears to be a strong one in terms of both physical traits and effectiveness.

Changeup:

Eighty-eight pitchers met the criteria for the changeup, and like the four seam fastball, there’s ample comparisons readily available to Stroman — 11 had a comp score below 1.00. The best fits based on physical characteristics belong to a pair of current Padres, Andrew Cashner and James Shields. Interestingly, Shields, who recently signed a massive contract, is best known for his outstanding changeup, with Jordan Gorosh of Baseball Prospectus throwing a 70 (or plus-plus) grade on the pitch as part of his Hot Stove Scouting Report. The 0.24 comp score is the second best of the four pitches examined thus far, and the outcome data shows an even stronger correlation. In terms of whiff and groundball rate, Stroman and Shields are almost perfect matches. There remains a significant discrepancy in usage with Shields throwing it 21.91% in 2014 versus Stroman’s 6.79%, but the fact that Stroman’s fifth favorite weapon is almost a twin of the pitch that was key in earning another guy seventy-five million dollars should offer Blue Jays fans all kinds of warm and cuddly feelings inside.

Curveball:

Stroman’s curveball is the primary reason I wanted to conduct this analysis and write this article after reading Sullivan’s first Hernandez/Alvarez foray into signature pitch comparisons. In my Marcus Stroman article published January 26th, I had this to say with respect to his breaking ball (with bold for emphasis):

It’s impossible to know from an outsider’s perspective, but I’ve maintained the belief that his slider and curveball are one in the same; simply thrown from different ends of the velocity band. The two have similar shape, with the curveball having amplified movement due to its reduced speed. It’s reminiscent of Jose Fernandez’ breaking ball, a pitch that doesn’t fall into the traditional slider or curveball mould, and is known simply as “The Defector.” With that being said, given its majesty, the particulars of Stroman’s breaking ball are deserving of their own discussion in a future post, not an addendum to this one.

This is obviously that post, and I must say, it’s pretty damn cool to have a personal observation be validated to this degree by mathematics; evidently you learn a thing or two watching baseball for 15 years. Of the one hundred and four right handed starting pitchers to throw at least 100 curveballs last season, a grand total of one — Jose Fernandez — had a comp score within 1.00 of Stroman. In fact, it’s basically just Stroman and Fernandez together with the rest of the pack outside the field of vision. They were nearly identical in average velocity (ranking 4th and 3rd, respectively), horizontal movement (within six one-hundredths of an inch), and groundball rate. The difference in whiff rate is a significant one, but this variation likely comes down to comfort and command. In his rookie 2013 season, Fernandez’ whiff rate on curveballs was 33.90%, not dissimilar to the rate Stroman produced in his first year. While this doesn’t necessarily mean Stroman’s curveball will take the same leap in 2015, you can draw your own conclusions from the chart below.

Slider:

The sixth and final pitch from Stroman’s fascinating repertoire is his slider, the pitch he became famous for with both Duke University and Team USA. The sample size for the slider was 97 pitchers, and at 88.25 miles per hour, Stroman’s was the 5th hardest on average. An interesting trend emerged with the slider, only part of which is evident on the table above. Between Stroman and the nine most comparable sliders, five were either thrown by 2014 Blue Jays starters (Stroman, Hutchison, Morrow, McGowan) or starters developed by the Blue Jays (Henderson Alvarez), so it’s possible we’ve stumbled upon a specific slider grip utilized by the coaching staff and taught to young pitchers as they grow within the organization.

Chris Archer has the best comp score at 0.82, and is the only pitcher below the “really good match” threshold of 1.00 we’ve been using. Still, of the six pitches, Stroman’s slider has the weakest connection to the sample population. Even Archer, whose physical traits show some parallels, is completely different in terms of effectiveness. Archer and the next three most similar comparables all get significantly more whiffs on their sliders, while Stroman’s is far more effective as a groundball weapon. Additionally, the slider has become Stroman’s least thrown pitch at just 6.74%, while his five best comps threw it between two and five times as frequently.

Even without a good match for the slider, a single pitcher possessing Johnny Cueto’s four seam fastball, Jacob Turner’s (or Roy Halladay’s) sinker, Jenrry Mejia’s cutter, James Shields’ changeup, and Jose Fernandez’ breaking ball — as well as above average command — is a stupefying package bordering on the absurd. I’ve never before written so much and so frequently about one player, and I’m sure even Blue Jays fans have started to tire of the constant fluff pieces regarding the staff’s new ace, but Stroman has become our version of the Power Rangers’ Megazord. Deep below the Rogers Centre concrete prior to every start, Marcus Stroman summons the best pitches from across the universe, assembling into a heroic figure capable of protecting our city and ridding it of evil — or the Red Sox; probably mainly the Red Sox.