Although the Nationals just lost three out of four to the Braves and are still running in second place behind Atlanta, things have generally been going Washington’s way lately. Since starting the year 11-16, they’ve gone an NL-best 22-9 (.710) with the majors’ third-best Pythagorean winning percentage (.685) in that span. They’ve dealt with a slew of injuries, but Anthony Rendon is back, 19-year-old Juan Soto has made an impressive splash, the Matt Adams/Mark Reynolds tandem has significantly outproduced the absent Ryan Zimmerman, and both Daniel Murphy and Adam Eaton could rejoin the lineup soon.

Yet Bryce Harper remains an enigma — a productive enigma, to be fair. The 25-year-old right fielder leads the NL with 18 homers. Despite a torrid start to his 2018 season, however — he hit eight homers in his first 17 games — he’s just 11th in the league in wRC+ (134, on .232/.371/.527 hitting), sixth in slugging percentage, 16th in on-base percentage, and tied for 27th in WAR (1.4). Not thrilling, but nice — after all, Harper is a career .281/.385/.516 (141 wRC+) hitter who last year batted .319/.413/.595 (156 WRC+). We all know that he’s capable of more than what he’s shown this year. Hundreds of millions of dollars, in the form of his next contract, are riding on it.

The direction of Harper’s trend this year is unmistakable:

Harper went from hitting .247/.458/.528 (158 wRC+) in April to hitting .223/.289/.563 (125 wRC+) in May, but those monthly splits conceal a more drastic falloff, albeit one that relies upon selective endpoints, which are displayed here for the purposes of rubbernecking only:

Harper’s Selectively Sampled Hot Start, 2018 Period PA HR BB% K% AVG/OBP/SLG wRC+ Through April 17 78 8 26.9% 14.1% .315/.487/.778 221 Since 178 10 14.6% 24.7% .201/320/.436 98

Woof. Lately, Harper’s funk is even deeper. Over his past 10 starts (plus one pinch-hitting appearance), he’s hitting .209/.271/.442 with four walks and 21 strikeouts in 48 plate appearances.

Turning away from those arbitrary swatches of playing time, a number of things stick out about Harper’s performance. For starters, he’s seen the lowest percentage of pitches in the strike zone than any batting-title qualifier in the league, just 38.0% of all pitches. This itself is nothing new: his 39.4% from 2015 to -17 combined was the majors’ lowest as well. Because he’s seeing so few strikes, he leads the NL in walks (18.4%), the second-highest rate of his career behind 2015 (19.0%). Meanwhile, Harper’s overall 21.5% strikeout rate is comparatively modest, ranking 31st out of 73 NL qualifiers, and just one percentage point above his career mark.

But as you can see from the table above, he’s been anything but consistent in terms of walks and strikeouts along the way. Looking at his “monthly” plate-discipline splits (found via our enhanced game logs), as well as his walk and strikeout rates, it appears that while seeing just about the same rate of strikes, Harper has suddenly gotten a whole lot less selective:

Harper’s Plate Discipline, 2018 Period BB% K% O-Swing% Z-Swing% O-Contact% Z-Contact% Zone% Through April 30 29.0% 16.0% 24.5% 72.9% 48.7% 75.7% 37.6% Since 7.2% 27.2% 32.7% 81.2% 56.3% 85.6% 38.5% Career 14.3% 20.5% 30.7% 73.3% 61.5% 85.1% 38.6%

Those seasonal segments are of more equal size than the first table, with 131 PA through April and 125 since. Harper went from walking nearly twice as often as he struck out to striking out nearly four times for every walk; last summer’s injury-abbreviated August and September aside, he hasn’t had a ratio like the latter since August 2014. He may have gone from swinging too infrequently (42.7% through April) to too often (51.4% since), although those are relative terms given his generally disciplined approach.

Looking at his overall season rates, while Harper is swinging at more pitches than ever inside the zone (77.0%, up from a career mark of 73.3%), he’s making less contact against those strikes than ever (81.0%, down from a career mark of 85.1%). Those trends are represented by the yellow and light blue lines, respectively:

Meanwhile, Harper is swinging with fairly typical frequency at pitches outside the zone (28.6%, a bit below his career mark of 30.7%) but making much less contact against those pitches than ever before (53.0%, compared to a career mark of 61.5%). Those trends are represented by the red and dark blue lines, respectively.

The overall result for Harper is less contact than ever before (70.5%, compared to a career mark of 75.6%) and the second-highest swinging strike rate of his career (13.5%). He’s at or near his career highs in whiff rates against sliders (21.7%), cutters (20.0%), four-seamers (10.0%), and sinkers (10.3%), with a huge spike in sinkers from righties (18.0%, up from a career mark of 6.9%) even while seeing fewer of them (13.3%, compared to 21.3% for his career), and a smaller spike in sliders from lefties (from 22.1% to 25.8%) while seeing them a fairly typical 26.7% of the time.

As for when Harper connects, obviously, the power is there: his .295 ISO is higher than any season except 2015 (.319), and his average exit velocity of 92.0 mph is his highest of the Statcast era, up from 90.6 mph last year. Likewise for his .425 xwOBA and his 17.0% barrel rate. Nonetheless, his .215 BABIP is the league’s fifth-lowest mark, 101 points below his career mark and 141 points below last year.

The big factors in Harper’s results on contact appears to be with regards to pull hitting and the infield shift. Generally middle-of-the-pack when it comes to his pull tendency — his 40.4% from 2015 to -17 ranked 115th out of 232 qualifiers — he’s currently pulling the ball at a career-high 46.4% rate, one point above what he did in 2015. Because of that, he’s being shifted against with greater frequency, and it’s not going well:

Harper Versus the Infield Shift Season Tot PA Shift PA Shift % BABIP wRC+ 2015 654 125 19.1% .384 148 2016 627 223 35.6% .269 59 2017 492 157 31.9% .344 107 2018 256 118 46.1% .229 32

The results above don’t include home runs — and, to be fair, according to Statcast, 13 of Harper’s 18 dingers have come when the shift was deployed. Without those homers, his wOBA against the shift is a grim .220. With them, and with the walks he draws when the shift is on (20 of his 39 non-intentional ones according to Statcast, which recently added pitch-by-pitch shift data), it’s .377, and .371 overall — a bit below his .382 career mark, and well below last year’s .416. In other words, the strategy of shifting against this pull-happy version of Harper more often does appear to working.

Whether Harper is consciously trying to pull the ball more or if he’s gotten into some bad habits that are causing him to pull, I can’t say. Likewise for whether that pull-happiness is having an impact on his whiff rates. For what it’s worth, he appears to be seeing — and whiffing on — sinkers with very similar frequencies whether or not the shift is on.

One thing that’s worth wondering about amid all of this is Harper’s eyesight. He’s worn contact lenses for a long time, but in the opener of a May 19 twinbill against the Dodgers, he donned glasses for the first time. After going 1-for-4 with a pair of strikeouts, he was back to contact lenses for the nightcap, and I couldn’t find any other game in which he’s worn them since. Like the rest of us, maybe he simply prefers contacts for his TV appearances.

Regardless, Harper is still a productive hitter. Perhaps all of this will even out over time, but to these eyes, if he’s going to get back to his usual threat level, he’s either going to have to figure out a way to improve his results against the shift or how to avoid facing it with such regularity.