15 July 2014

Dissecting J.J. Hardy's Homer Drought

For a player whose offensive value is all but predicated upon the long ball, the lack of pop coming out of J.J. Hardy's bat this season is troubling. Finally getting off the schneid June 21st with a home run off of a 95 MPH fastball, Hardy has followed up this long fly with two more, bringing his home run per flyball rate (HR/FB%) up to 2.9 percent, putting him in the hallowed homer company of Ben Revere (2.9%) and Austin Jackson (3.0%). Sarcasm aside, the dearth of home runs currently has Hardy—whose 25 home runs last season tied him with Troy Tulowitzki for the most hit by a shortstop, and his 12.4% HR/FB rate ranking third for shortstops last year—hitting at a .298 weighted on base average (wOBA) and 84 weighted runs created plus (wRC+), both of which are slightly above American League average for shortstops (.293 wOBA and 83 wRC+). Combine this with a career-worst 3.8 percent walk rate and a slight hike in his strikeout rate (15.7%) compared to last year and his career (14.3% and 11.3%, respectively) and it becomes obvious that Hardy's normal sources of production are beginning to run dry.

There are myriad reasons for Hardy's power outage—injury, age-related declines, a loss of bat speed, a change in how he is being pitched, changes in his batted ball rates, perhaps a change in hitting approach—all of these variables that could be at the root of the problem, working alone, or in unison. While we don't have access to all of the information that could determine whether some of these factors are realistically a piece of the homer puzzle for Hardy, we do have batted ball and PITCHf/x results to work with, which can help discern whether the problems are more hitter- or pitcher- derived. Using last season for comparison here and moving forward, let's start by looking at pitch type linear weights (here, we use PITCHf/x-derived pitch values per 100 pitches) of the pitches Hardy has seen; the more positive a number, the more success Hardy has had with a given pitch:

Season wFA/C wFT/C wFC/C wFS/C wSI/C wSL/C wCU/C wKC/C wCH/C wKN/C
2013 -0.16 0.56 -2.01 -7.48 2.02 -0.68 3.53 -2.25 -0.28 8.14
2014 -0.83 -1.36 -1.76 -1.68 1.05 2.06 1.71 -5.5 -1.02 -10.08
Career -0.24 -0.16 -0.94 -2.57 -0.43 -0.2 0.3 0.58 0.35 5.42

 FA=fourseam fastball, FT=twoseam fastball, FC=cutter, FS=split-finger fastball, SI=sinker, SL=slider, CU=curveball, KC=knuckle curve, CH=changeup, KN=knuckleball

Here, we see a slight decline in Hardy's success with fastballs, especially fourseamers, twoseamers, and to some extent, sinkers; cutters and split-finger fastballs are still problematic (hence, the negative values), but this year appear to be less so than in years past. Sliders appear to be quite improved in terms of Hardy being able to put a good swing on the pitch, with this and the decline in fastball success perhaps a tacit indication that the bat speed might be starting to decline in 2014. 

Staying with PITCHf/x data, let's now turn attention to how often these pitches are seen by Hardy, which will also provide more context to what's he seeing, pitch-wise, as it is one thing to do poorly against a certain pitch, but only see the pitch once or twice a season:

Season FA% FT% FC% FS% SI% SL% CU% KC% CH% KN%
2013 35.70% 15.60% 6.40% 1.20% 8.20% 14.50% 5.50% 0.50% 10.60% 1.00%
2014 38.30% 17.30% 5.20% 1.40% 7.40% 15.80% 6.10% 0.80% 7.20% 0.40%
Career 44.90% 9.10% 4.40% 0.70% 5.70% 16.70% 8.10% 0.20% 9.40% 0.40%

Hardy is seeing slightly more four- and twoseamers than last year, with a concomitant rise in sliders and curveballs seen; it appears that Hardy is making the most of the increased number of sliders he is seeing, but is doing so at the cost of less success against the hard stuff so far this season. 

So far, we have found some slight deviations in how pitchers have gone about getting Hardy out; have these changes been reflected in the batted ball data, aside from the homers?

2013 16.60% 45.20% 38.20% 14.40% 12.40% 8.40% 0.00%
2014 17.70% 43.90% 38.40% 16.30% 2.90% 8.40% 50.00%
Career 16.90% 44.40% 38.70% 13.30% 10.80% 7.40% 15.40%

LD=line drive, GB=ground ball, FB=fly ball, IFFB= infield fly ball, IFH=infield hit, BUH=bunt hit 

In a word, no; the Hardy of 2014 appears to be the same as the Hardy of 2013, at least by his batted ball rates, outside from HR/FB. The rise in bunt hits seen this year is courtesy of two bunt hits, compared to zero laid down in 2013. The more commonly referenced and researched numbers of Hardy's 2014—line drive, ground ball, and fly ball rates—are all within a percentage point or two of last year's rates, which saw him enjoy his typical homer-heavy production. Going one step further and calculating fly balls per popup, which provides a rough estimate of how hard a player is hitting the ball—and the results indicated that perhaps it isn't so much the batted ball type at play with Hardy's homer drought, but more the quality, with respect to how hard it's being hit. 

Season FB% IFFB% FB/PU
2013 38.20% 14.40% 2.65
2014 38.40% 16.30% 2.36
Career 38.70% 13.30% 2.91

Overall, Hardy's FB/PU is fairly pedestrian compared to the likes of a slugger like Chris Davis, whose current FB/PU sits a 6.59. However, we do see it in decline, sitting at 2.36, his lowest rate as an Oriole; in his Oriole years, Hardy has averaged a 3.0 FB/PU rate, suffering a career-low 2.05 FB/PU in 2006, while with the Milwaukee Brewers.

Setting aside the tables for a moment, let's look at where in the strike zone Hardy's homers have been hit this season and last, splitting out pitcher handedness:

 While we don't have much 2014 data to hang our hats on, we can use 2013 as a template—Hardy does the most damage on fastballs (here, I collapsed all fastball types into a single 'FA' variable) up in the zone, essentially over the middle of the plate, from righthanded pitchers. Through Brooks Baseball and with a focus on fastballs, we can compare where righties are pitching to Hardy to see if they've become cognizant of this trend and have begun to avoid the high fastball; on the left is 2013 data, on the right, 2014:

Pitchers have appeared to maintain the same or at least a similar approach to getting Hardy out with respect to pitch location, with no significant swings in fastball location from last season to now. 

Using the same PITCHf/x tools, let's take a look at Hardy's tendencies; here, we look at his popup rates over the last season and a half on fastballs from righties:

It appears Hardy has had a little tougher time this year putting a good swing on fastballs in the heart of the plate and slightly elevated, his homer 'sweet spot'. While the statistics previously presented have shown that he has been able to counter some of this in the greater scheme of things offensviely, given that his line drive and fly ball rates have been fairly par for the course in 2014, the PITCHf/x data alludes to a possible slowing of the bat for Hardy, paired with a propensity for hitting balls with less authority this year. 

For Hardy, the sudden decline in his bread and butter offensive weapon is jarring and is made all the more discouraging, given his less than optimal walk rates and ability to hit for average. While the Orioles shortstop still has the potential to finish the season as an above average offensive contributor, the numbers are pointing to the days of 20+ homer seasons being over, unless adjustments are made in his approach.

Data courtesy of Baseball Savant and FanGraphs, unless otherwise noted.


Anonymous said...

I'm sure bat speed is a problem.

His contact rates have fallen a bit this year, too. SwStr% is up to a career high mark at 7.2%. Also, his contact rate on pitches outside of the zone has fallen drastically: 75.8% ('13) vs 62.7% ('14)

That's a huge drop off.

I'm surprised that you place more importance on pitch values than contact rates. I guess I still don't trust pitchf/x's pitch identification as much as I trust its pitch location.

Jon Shepherd said...

Anon - what sample size do you think we need to say those differences are meaningful?

Stuart Wallace said...

Anon - Yes, that's a great observation on the outside contact rates. He's seeing more pitches in the zone and with the FB/PU stat combined with the pitch type linear weights variability compared to 2013 felt that was a more compelling reason for the decline. Looking at where in the strike zone Hardy was hitting most of his homers in 2013, I also felt that outside of the zone contact rates played a lesser role in these declines. That being said, the pitch type linear weights are not a predictive thing and don't correlate strongly year-to-year, so it isn't a be-all, end-all stat.

I will also concede that this could be just a mechanical thing before it's an age thing regarding the possibly slowing bat.

Thanks for your thoughts!


Anonymous said...

I'm not sure when pitch values "stabilize" (maybe y'all can inform me) but I know contact rates are meaningful by this point in the season.

I also forgot to mention JJ's HR/FB avg. distance has also fallen by 5 ft. from last year.

For the record, I like this article a lot and wish I had the time to write stuff like this (rather than just use it for fantasy baseball gains). Thanks guys.

Jon Shepherd said...

That is really a topic up to some contention. There is decent evidence that projections before the season are more accurate for future performance than a half season of data.