Trevor Story and Sample Size
Trevor Story hit another homer last night, his league-leading eighth home run of the season. That’s eight home runs in just 13 games, totaling 59 plate appearances. He also hit a double, giving him 12 extra base hits on the year; Josh Donaldson is the only other player in the majors in double-digits, and he has 10. At this point, it’s pretty clear that, while still a player with holes in his swing, Trevor Story hits the ball really hard when he does make contact.
Last night’s home run, for instance, was hit at 108 mph. It was the eighth ball he’s hit this year that left the bat with an exit velocity north of 105. For reference, here is the full list of the 13 players that already have eight or more balls hit at 105+.
| Player | Results | Total Pitches |
| Carlos Gonzalez | 15 | 215 |
| Domingo Santana | 13 | 230 |
| Mark Trumbo | 12 | 178 |
| Manny Machado | 11 | 175 |
| Carlos Correa | 10 | 189 |
| Gregory Polanco | 9 | 223 |
| Josh Donaldson | 9 | 248 |
| Trevor Story | 8 | 245 |
| Giancarlo Stanton | 8 | 219 |
| J.D. Martinez | 8 | 169 |
| Bryce Harper | 8 | 186 |
| Danny Valencia | 8 | 160 |
| Jonathan Schoop | 8 | 147 |
Maybe this should be a post about Carlos Gonzalez? Story is putting balls over the fence, but CarGo is absolutely crushing the ball right now. Anyway, his ridiculous teammates slugging performance aside, Story is mostly keeping company with some of the best sluggers in baseball, and then a few surprising names. Danny Valencia, for instance, is hitting .273/.333/.295 and has just one extra base hit so far, suggesting that he’s both been a bit unlucky so far but also that scorched ground balls — he’s at a 55% GB% for the season — are not as valuable as balls crushed in the air, and a reminder that exit velocity alone isn’t going to give us the whole picture.
Thankfully, MLB is now also releasing launch angle for every play, and Baseball Savant allows you to add launch angle as a filter in the Statcast search. So, if we look for just balls hit at 105 and with a launch angle of at least 20 degrees, we find a somewhat different leaderboard.
| Player | Results | Total Pitches |
| David Ortiz | 5 | 202 |
| Trevor Story | 5 | 245 |
| Mark Trumbo | 5 | 178 |
| Josh Donaldson | 5 | 248 |
These four players have combined to hit 20 balls in play with at least a 105 mph exit velocity and a greater than 20 degree launch angle; 15 of the 20 have gone over the fence. This is the kind of ball that is almost always a home run, and Story’s combination of an uppercut swing with the ability to hit the ball square suggests his power is not a fluke. You don’t fake your way onto a list with guys like Ortiz, Trumbo, and Donaldson, even in a baker’s dozen worth of games.
Of course, we don’t have a long history of Statcast data, so we can’t look back at Chris Shelton’s 2006 season and see how often he was crushing the ball back then. We don’t know how predictive this stuff is yet, though as Russell Carleton noted this morning, it appears that exit velocity is the kind of number that doesn’t need a massive sample size, and we know batted ball rates stabilize pretty quickly, so it would seem likely that launch angle is also going to be more meaningful earlier in the season than most results-based metrics.
And the fact that Story has hit five balls in just two weeks within this sweet spot for home runs suggests that he might just have some pretty special power for a middle infielder. For even more context on what these kinds of numbers can mean, here is the full list players who Statcast recorded at least 20 balls in play at 105+ EV/20 degrees last year.
| Player | Results | Total Pitches | % of Pitches |
| Chris Davis | 42 | 2786 | 1.5% |
| J.D. Martinez | 29 | 2605 | 1.1% |
| Nelson Cruz | 29 | 2627 | 1.1% |
| Yoenis Cespedes | 26 | 2722 | 1.0% |
| Mike Trout | 26 | 2981 | 0.9% |
| Kris Bryant | 25 | 2663 | 0.9% |
| David Ortiz | 24 | 2485 | 1.0% |
| Paul Goldschmidt | 23 | 2917 | 0.8% |
| Giancarlo Stanton | 21 | 1221 | 1.7% |
| Edwin Encarnacion | 21 | 2517 | 0.8% |
| Josh Donaldson | 21 | 2817 | 0.8% |
| Miguel Cabrera | 20 | 1985 | 1.0% |
One thing is clear; Story isn’t going to keep hitting balls in this range at the same rate he has been so far. Stanton is the king of crushing baseballs, and if he couldn’t get over 1.7% of all pitches in this crushed ball sweet spot, then Story won’t stay over 2.0%. Realistically, even the best sluggers in the game are down closer to 1% of their pitches being put in play in this range, so despite his strong start, it’s probably not prudent to be projecting Story to be significantly above that going forward. But it’s also worth noting the kind of crowd he’s putting himself into; guys who hit the ball regularly in this exit velocity/launch angle range hit for a lot power, with no exceptions.
But because we’re dealing with such a small sample, you have to be careful to not get too over-exuberant, even with metrics like these that won’t take as long to reveal real skill.
For instance, last year, Brett Wallace hit five balls out of 428 pitches seen in this 105/20 range; at 1.2% of the pitches he saw last year, it wasn’t exactly the same kind of rate as Story has started off 2016, but it would have put him in that elite group as well if extrapolated out. He’s currently a bench player for one of the worst teams in baseball. Jarrett Parker hit four balls out of 226 pitches (1.8%) seen in this range, and he’s currently batting .119/.176/.143 in Triple-A. Hitting the ball hard for a few weeks isn’t a guarantee of success.
But at the same time, if Brett Wallace or Jarrett Parker could play shortstop, they’d probably be big leaguers. Both project as roughly league average hitters, and aren’t in the lineup because league average hitters with minimal defensive value aren’t that useful. League average hitters who can play shortstop? That’s another story entirely.
(Come on, you didn’t really expect to get through this whole post without a pun about his last name, did you?)
And right now, both ZIPS and Steamer think Story is something close to a league average hitter. Prior to the season, ZIPS had Story at an 86 wRC+, while Steamer checked in at 82. The rest-of-season ZIPS forecast, incorporating the results of the first 13 games, bumps Story’s wRC+ up to 94, while Steamer is more cautious, only going up to 87. Steamer thinks the sky-high strikeout rate is a bit more real than ZIPS does, while ZIPS puts a little more weight on the power, giving a 26 point spike in SLG as opposed to the 20 point increase that Steamer’s adjustment includes.
For additional context, I reached out to Dan Rosenheck, who has argued that by looking at the right kind of numbers within small samples, you can still identify significant changes even in spring training data. He’s also got Story’s SLG going up by roughly 20 points — he quoted a 19 point increase to me yesterday, but that was before Story had another double and a homer last night — and his rest of season forecast is in line with what ZIPS is projecting.
While no one wants to fall into the trap of overreacting to two weeks worth of results, we also need to keep in mind that our opinions of a player’s abilities need to be constantly updating as those players provide new information. Small sample data isn’t meaningless, and refusing to budge off a pre-season forecast when a player provides evidence that he’s better or worse than that forecast is an overly stubborn position.
For two weeks, Trevor Story has provided some real evidence that he can hit the ball exceptionally hard in the air. The other guys who are doing this as often as he is are elite sluggers, and the guys who did it regularly last year are mostly All-Star caliber first baseman or corner outfielders. While Story’s contact rate remains a significant problem, we should be getting close to the point where we’re not doubting his power too much anymore. Small sample size is a good refrain to keep in mind when looking at a player’s results, but as we move towards an era where we can measure a player’s raw abilities with greater precision, the time it takes to identify high-level talents will be diminished.
It’s early, and pitchers might yet figure out how to exploit the holes in Trevor Story’s swing, but at this point, it’s probably safe to say that his power is not a fluke. He won’t keep hitting homers at his current rate, but Trevor Story is probably going to hit a lot of dingers this year.
Dave is the Managing Editor of FanGraphs.
Quite the story.
Curious why these crushed balls are presented as a percent of pitches seen. Wouldn’t this drag down the numbers of more selective sluggers that see a large number of pitches per PA? Or feared hitters with a large percent of pitches seen outside the zone that they shouldn’t be swinging at anyway?
Because I didn’t know that you could change the settings on Savant to show percent of balls in play until after I put up the post. So, my ignorance is basically the answer.
Could we see what those %s look like out of balls put in play, or as a % of flyballs only? It’s interesting even with the total pitches sample set, but perhaps we could see a larger trend for sluggers.
Would love to see this expanded upon in either the comments here or a future post, thanks.
I took a look at the percentages of BIP with the same minimum velocity and angle for the 2015 season. Chris Davis led with 11.35%. Stanton was 2nd with 11.23. Miguel Sano was 3rd with 9.26%. Nobody else managed to break 7%. The top 2 names are no surprise but the distance between them and the rest is.
Holes is his swing = rising fastball?
If he has an uppercut swing, a rising fastball would increase the angle between the swing plane and pitch plane
I don’t think the laws of physics allow any pitch to “rise” through the strike-zone
Pitches that drop less than expected by ballistics are said to “rise” in PITCHf/x parlance.
Story’s start reminds me of a couple seasons that Dexter Fowler had with the Rockies, where he went nuts in April/May with HRs, then disappeared completely from June on, his OBP being his only saving grace.
For Fowler, its always been that he owns the inside half of the plate from the Left side, where literally every homerun he hit was on the inner third, so within 6-8 weeks teams had scouting notes and would pitch him away to mostly weak contact. For Story, it seems he doesn’t have that seem easy scouting tell — he’s hit homers to opposite field, he’s hit homers off of curves, change-ups, and sliders — he just doesn’t seem to have that obvious sweet spot or weak spot. It may be that he just profiles like a swing and miss guy that is always a bit dangerous, he’s not going to winning batting titles, but is going to do some real damage in Coors.
Devil’s advocate, he’s only done it once in the last 10 days–the home run last night. Since 4/9, that 1 is out of 175 pitches or .57%, making him one of 82 players with a rate at least that high over that time frame. Of course, I am admittedly playing with arbitrary endpoints. His Hard Contact% and average exit velocity on non-grounders look pretty solid over this same time frame.
The new walls at Coors have only cost two HR’s so far, both were hit by Story during that time frame.
Question: instead of having % of total PITCHES at 105+ EV/20 degrees, wouldn’t it be more informative to have the % of total SWINGS? For a patient hitter, he would show up low in % of total pitches, since a lot of those pitches won’t be swung at.
Ok, when I posted this yesterday, I SWEAR the other post that is showing up as being posted EARLIER than mine was NOT here, and wasn’t here an hour later either when I checked back to see if my question was answered. I wonder how that happened.
Don’t balls travel 8% faster at altitude? Is the exit speed adjusted for Coors field?
There’s less air resistance, so they travel further, but bat speed shouldn’t be effected by air density (except if the bat is somehow being effected by drag… which I doubt.
Yes; this is why Aroldis Chapman famously hit 112 mph in his July 25th appearance at Coors Field last season.
I’d say it doesn’t really matter. I would think the goal right now is to figure out what Story is/will be the rest of the season, not so much what he truly is playing in a world of normal physics.
In that regard, all that matters is what he’s typically doing, both at home and on the road.
I’m having trouble finding the launch angle field on the Baseball Savant website.
Is it a field on this web page? http://baseballsavant.com/pitchfx_search.php
Is it labeled “Launch Angle” or something similar?
Under applications, go to batted ball leaderboard. Now, at the top of the screen you should see statcast search. That’s what you want.
I have Story in a dynasty/keeper league. He’s currently on my inactive rookie squad. If I activate him, I’ll eat a year of eligibility and be required to roster him for rest of season.
Current SS are Eugenio Suarez and Ketel Marte (5×5, 12tm)
Overall – I’d project that I could finish middle of the pack with my current roster.
Do I activate – or does he cool off?
Thyrsus of Beckham said:
April 19, 2016 by 11:16
I have the history of the League of dynasty / keeper. He is currently in his beginner’s inactive units. If you’re not ready, I’ll eat the admissibility of the year, and he has planned for the rest of the season.
SS Eugenio Suarez now and Ketel and Marta (5 × 5 12 ™)
Overall – I can finish second package of projects with its current list.
For activer- or cool?
What’s interesting to me is Trumbo and Machado have more with far less pitches seen.