Andrew Benintendi has hit at every possible opportunity. He batted .564 as a high school senior in Ohio, becoming the National High School Player of the Year. After a respectable but unspectacular start to his college career at Arkansas, he slashed .376/.488/.717 in his sophomore season on his way to winning Baseball America’s College Player of the Year Award, the Dick Howser Trophy for the best national college player, SEC Player of the Year, and the Golden Spikes Award.

That college performance led the Red Sox to take him seventh overall in the 2015 draft. He handled the lower minors with ease, walking considerably more often than he struck out and quickly progressing to Double-A less than a year after he was drafted, where he hit .295/.357/.515 over 63 games. That earned him a promotion to the majors at the start of August 2016, where he just went right on hitting.

Benintendi has been an above-average hitter at every single one of those stops, including his first taste of the majors over those two months in 2016. That even goes for last year, when he perhaps underwhelmed given the extremely high standards his prior performance had set and he was both literally and statistically dwarfed by fellow rookie Aaron Judge, yet he still finished the year slightly better than league-average. 2018 has brought the best yet, as the Red Sox outfielder is currently around 40 percent better than average at the plate, supplying an .896 OPS as a key part of the Boston lineup.

There’s one puzzle Benintendi still hasn’t solved, for all his accomplishments: left-handed pitching. The 23-year-old has a career .618 OPS against southpaws, batting .215 with a limp .096 ISO. Up until the start of the 2018 season, he had just one home run and four extra-base hits in total against same-handed pitching.

While the batting average hasn’t improved, the power certainly has in 2018: Benintendi has quadrupled that home run total and added five more doubles, posting a .688 OPS against lefties this year. That indicates that some development may be taking place, yet it’s still rather disappointing and perhaps surprising given how terrific his overall line looks.

It’s not unusual for hitters to have issues against same-handed pitching, of course. The vast majority have some kind of platoon split in that direction, and only a rare few have a reverse split. Let’s see just how extreme Benintendi’s splits really are. Below are the ten hitters with the biggest negative difference between their True Average (TAv) against lefties and their overall mark (.260 is league-average) in 2018.

Benintendi has the third-largest negative difference between his TAv against lefties and his overall performance, and the fifth-biggest platoon split. The diversity of names on this list indicate that having splits this extreme doesn’t in itself tell us much about the overall quality of a player’s performance: clearly Martinez is here simply because he has been so astoundingly good against right-handers, while Altuve and Votto have been fine, if not spectacular.

What sets Benintendi and former teammate Travis Shaw apart is the fact that they are having excellent offensive seasons while still struggling to be remotely close to average against southpaws. The rest of these players have either been average overall or clearly below, or in the case of Benintendi’s two teammates and Joey Votto, set apart just as much by their remarkable production against righties.

When extended to career-long splits, Benintendi also stands out even compared to Shaw. The Brewers third basemen has a 78 tOPS+ against lefties: in other words he has performed 22 percent worse than his overall production over the course of his career. Benintendi is all the way down at 53. Below is a table featuring the active players with a mark at least as low (min. 200 PA).

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Generated 6/28/2018.

There are three career platoon players here in Joyce, Lind, and Adams, and two others who are clearly heading that way if significant improvements aren’t made in Pederson and Lamb. The most encouraging names are those with the identical tOPS+ numbers, Conforto and Schwarber. Both are similarly new to the majors and have each shown the ability to be excellent hitters at times. While Conforto battles the aftereffects of his severe shoulder injury, Schwarber seems to have settled in as a very productive regular with the bat, much like Benintendi.

This table also shows us how small the sample still is. Benintendi has the best plate discipline numbers of this group and, as we have already noted, is trending slowly in a positive direction. Still, “hits like Matt Adams against lefties” is not something that you want to say about any player, particularly one who otherwise looks like one of the finest players in baseball.

I’m being picky, of course. If Benintendi was a mediocre hitter overall then his line against lefties would not be notable. He wouldn’t have shown up with those other hitters with big splits, and nothing would look as extreme as it does. It’s the quality of his performance against righties that suggest there might be more to come. Even an average performance against left-handers would put him close to the likes of Altuve and Votto.

So where is Benintendi struggling against same-handed pitching? It’s not a huge whiff problem, as the table above suggests. He does strike out more against them, and the uptick in power this season has definitely come with an increase in strikeouts. At the same time, he still has a better walk percentage against lefties than righties over the course of his career.

It’s the quality of contact that appears more problematic. While not generating a ton of power against fastballs, Benintendi does have almost all of his extra-base hits versus lefties off fourseams and sinkers, and changeups rarely get him out: he has never struck out against a change from a left-hander.

The numbers against sliders, curves and cutters are the most incredible, and not in a good way. Per Brooks Baseball, Benintendi has 74 career at-bats ending with those pitches against lefties, with just nine hits and zero extra-base hits. The 23-year-old doesn’t just have diminished power against those pitches: he has none at all.

Bear in mind that these 74 at-bats are far from the only opportunities Benintendi has had: he has seen those pitch types 373 times from the left side, and swung at 133 of them. Consider also the fact that he has no problems with any of these pitches from righties, with ISO marks ranging from .141 on curves to an incredible .291 on sliders.

Given the small sample, it’s reasonable to ask whether this might not all just be a big fluke. Has Benintendi put some good swings on pitches and just seen a few of them caught on the track or taken away by impressive defensive plays? Here’s his wOBA and expected wOBA (xwOBA) against lefties, based on the Statcast data:

The only significant divergence is in 2016, when he was actually even worse than his numbers suggested. The improvement this season also appears to be largely unfounded and at this point we should note that Benintendi plays in a park with an xwOBA-confounding feature in the Green Monster.

The league-average wOBA mark is around .320, but for left-versus-left matchups, it’s actually .297 over the same period, so Benintendi isn’t all that different from his left-swinging peers over the past two seasons. Again, he’s more disappointing relative to himself. It is also his consistently above-average walk rate that props up this performance, which does not wipe away the problems he has with making good contact, although it does speak to his excellent approach.

It seems ever more telling that when Benintendi first came up, he was used primarily as a platoon player, and that briefly happened again when he was slumping midway through last year. Boston saw enough to indicate that he might struggle against same-handed pitching. There has definitely been a very clear plan of attack by opposing pitchers, and it’s the one you would expect, as the FanGraphs heatmap below shows:

It’s all low, and largely away. Those lefty sliders that he can’t do any damage on are sweeping away into that bottom left-hand corner, sometimes catching the zone, often missing but drawing whiffs or poor contact anyway. That, in turn, leads to a very predictable batted ball distribution that’s easy to defend:

Benintendi’s ability to hit a deep fly ball to right field has been almost completely taken away by this approach. On the rare occasion he has managed it, he has hit a home run. A lot of those pitches have still been pulled for weak groundouts, and he’s rarely driving the ball the other way for a hit. Instead, there are a lot of lazy fly balls on this distribution. Teams can also play him shallow and shade him to left in the outfield, knowing he’s incredibly unlikely to do any damage to right, while focusing on the right side of the infield for almost all of his ground balls.

Benintendi’s swing plane seems to be geared very well to deal with those pitches coming in from the right side and quite the opposite from the left. He has a very open stance, which ought to give him a better look at those pitches and allow him to pull the ball more easily, but might also make it harder for him to put a good swing on those pitches tailing low and away, where the majority are ending up and near-perfect timing is required.

Pulling the ball is also not a great approach when the pitches are located low and away, so that open stance might not be helping him all that much as clearly he cannot generate that power to right.

When lefties do get it wrong and leave something a little more inside and up in the zone, this can happen:

The bat speed is not an issue. Jesse Biddle misses his spot by a mile and Benintendi punishes it, although again he does not pull the ball but hits it to dead center, where it could easily have stayed inside the park and almost did.

In addition to being a problem with pitch location, Benintendi’s tendency to only hit the ball in the air to center or left suggests that he is simply getting his timing wrong far too regularly. It’s harder to time swings to get the sweet spot against same-handed pitching and Benintendi may just need more looks against major-league quality southpaws to work on that timing.

It is not as though teams can do a huge amount to directly counteract Benintendi with a lefty, sandwiched as he normally is in the lineup between Mookie Betts and Martinez. Despite Martinez’s numbers above, as a right-handed hitter he normally hits lefties better, and the same goes for Betts (they are both, of course, excellent regardless of handedness). Xander Bogaerts has also historically had a relatively pronounced split in favour of lefties. No manager is going to be all that happy about bringing in a lefty to face Benintendi and then leaving them out there to take on Martinez, so short of employing a LOOGY, it’s not an easily-exploitable flaw.

That doesn’t diminish the fact that Benintendi still isn’t a particularly useful contributor against southpaws. His numbers pale in comparison to someone like Steve Pearce, who the Red Sox just traded for. Pearce has a career .841 OPS against lefties in addition to better strikeout numbers than the man over ten years his junior. Up to this point, Boston has not really had a viable bench option to call upon against left-handers, especially when Brock Holt is not starting (and Holt is barely league-average against lefties for his career anyway). It should not be inconceivable that Pearce replaces Benintendi in big spots against left-handers the rest of the way.

Benintendi is also yet to turn 24 and the fact that he is among the major league’s best run producers is a testament to the overall quality of his approach and his ability to take a walk even when he is struggling so significantly elsewhere against lefties. It’s far from remarkable that a left-handed hitter is having trouble with left-handed pitching. In this case, it’s remarkable primarily because of just how easily everything else has seemed to come to Benintendi. Given time, he should conquer this weakness too.