The A’s Might Have the Next J.D. Martinez

Me, I’m kind of sick of hearing about J.D. Martinez. I’m sick of hearing about all the free agents. All I want is for the ones who’ll get jobs to get jobs so that we can move on with all our affairs. Seems like Martinez is destined to end up in Boston. Arizona is reportedly trying to stay involved by playing with what present and future money they have, but you can never really tell what information is just out there because Scott Boras wants it to be. It would remain surprising if Martinez doesn’t spend 2018 in a Red Sox uniform. Someone will simply have to give in.

To Martinez’s credit, a lot of us probably do take him for granted. When you talk about free agency, you talk about the future, but Martinez has put together a remarkable past. At least as far as the recent era goes, Martinez is among the original so-called swing-changers. He’s a daily reminder that even the Astros don’t get everything right. And, since 2014, 289 players have batted in the majors at least 1,000 times, and Martinez has ranked fifth in wRC+, between Bryce Harper and Paul Goldschmidt. Martinez isn’t much of a runner, and he isn’t much of a defender, and he turned 30 years old in August. Guy can hit, though. He was perfect for the home-run era, even before the era began.

That’s an introduction about J.D. Martinez. Now let’s use him to talk about somebody else.

Martinez, clearly, is one of the better hitters around. That much is evident, no matter where you look. But for no real good reason, I got to wondering which hitters are similar to him. I didn’t have any conclusion in mind. I wasn’t sure where the numbers might lead. It was sort of aimless spread-sheeting, on a day with little else to do. I went back to an old methodological well.

What are some distinguishing traits, as hitters go? One, I’d say, is exit velocity. Another is launch angle. To get that information, I used Baseball Savant. But those numbers don’t tell us much about approach or discipline. So for a third trait, there’s contact rate. And, for a fourth, I like in-zone swing rate minus out-of-zone swing rate. You could argue for out-of-zone swing rate alone, or for regular swing rate alone, but, just stick with me. This is all experimental. I just like where this approach took me.

I gathered 2017 regular-season data for every hitter who hit at least 100 batted balls. For all four statistical categories, I calculated the standard deviations, and then I compared every hitter to J.D. Martinez. For every hitter, for each of the four stats, I found the absolute value of the difference, in standard deviations. Then, at last, I added the four values up, to generate something of a comp score. The lower the number, the stronger the comparison. No, of course this isn’t perfect. Of course there are elements the analysis leaves out. But I also like this for its relative simplicity. And so with no further delay, here are the ten most similar hitters to 2017 J.D. Martinez.

J.D. Martinez 2017 Comparables
Player EV LA O – Z% Contact% Comp Score
J.D. Martinez 91.2 15.4 40.9% 70.7%
Matt Olson 90.5 14.9 38.9% 70.0% 0.9
Khris Davis 92.1 14.2 43.3% 69.0% 1.4
Josh Donaldson 90.5 13.6 38.2% 74.4% 1.8
Gregory Bird 89.7 20.2 40.6% 71.3% 1.8
Cody Bellinger 89.6 16.2 36.2% 69.7% 1.8
Justin Upton 88.6 15.5 36.8% 71.7% 2.0
Domingo Santana 89.4 10.2 41.3% 70.0% 2.1
Jorge Bonifacio 87.7 14.4 43.4% 70.7% 2.1
Freddie Freeman 89.7 15.8 43.2% 76.5% 2.1
Nelson Cruz 92.8 12.4 36.3% 70.6% 2.2
SOURCE: Baseball Savant
Exit velocity and launch angle taken from Baseball Savant. Minimum 100 batted balls.

Because this is something I made up, it’s not like we know what a “close” comp score is, generally speaking. A comp score of 2.0 or 5.0 doesn’t immediately mean anything, in the way that a .300 batting average would. Yet still, a leaderboard is a leaderboard, and there are a lot of quality hitters in that list. As, I suppose, there should be. I’m guessing Boras wants to sell Martinez as someone who could age like Nelson Cruz. As you look at the table, you see that Martinez’s second-closest comp is Khris Davis, by a decent margin. There’s just one more name in front of him. Martinez’s most comparable hitter would appear to be Matt Olson. Olson’s the only guy with a comp score under 1.

Across the board, the numbers are almost identical. And Olson, in case you missed it, generated a 162 wRC+, over the limited sample of 59 games. When you see that kind of performance, and you see that kind of sample size, you’d be right to mentally fold in some regression. Probably the most unsustainable element of Olson’s rookie season was his hitting just two doubles to go with 24 homers. But this analysis is also supportive. Olson hit the ball very hard. Can’t fake that. Olson put the ball in the air. Always has. Olson made a below-average rate of contact, but that rate wasn’t low enough to sink him, even against the most advanced competition he’d ever seen. Never mind the triple-slash line; just based on skills, Olson as a rookie was believably good. Here is Matt Olson at his rookie peak.

Between Olson and Martinez, the offensive profiles are similar, with track record being the major difference. Of course, there are more differences beyond that — Olson’s a lefty and Martinez is a righty, and Martinez runs a little faster. Martinez, also, has been a threat to all fields, while rookie Olson was mostly just a threat to right and up the middle. Martinez, lastly, is more aggressive, more willing to go after the first pitch. Maybe that’s something Olson could learn, or maybe it’s something Olson prefers not to do. No two players are exactly alike, and Matt Olson will chart his own course.

It’s not as if Olson and Martinez are linked by fate. Martinez has blossomed into something extraordinary, and Olson’s still in the process of proving himself. The takeaway for me, however, is that if Olson does manage to keep it together, he could be the specific kind of threat Martinez has been. The swing and miss will stay there, almost certainly, but any given contact could mean four bases. The evidence is in the table above. Olson has shown he has the skills. As we prepare for the season ahead, I find myself intrigued by the A’s. I don’t know if they can actually mount a wild-card run, but what they’ve been missing is stars. Olson looks like a partial solution to that.

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Jeff made Lookout Landing a thing, but he does not still write there about the Mariners. He does write here, sometimes about the Mariners, but usually not.

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The conclusion I get from the article is that Khris Davis has been changing his jersey and pretending to be another player so that he could hit twice in the lineup.


Amazing what swinging from the left side can do for one’s complexion!


Olson’s arm is way better.


He was a fantastic pitcher in high school. He once started against us and opened with 25 straight strikes. I don’t think he threw a ball until there was two outs in the 3rd inning.