Imagine you’re magically granted the power of time travel and that you use it to visit the days leading up to Opening Day 2016. Suddenly back in a world without daily regular-season baseball, you approach an unsuspecting baseball fan and tell them that you’re a time traveler with this bit of baseball information from mid-June: over the past 30 days, the Nationals have had the best offense in the National League.

The fan, presumably, would begin by chastising you for having wasted the gift of time travel on something so frivolous. Then, after gathering him- or herself, would likely respond with something like, “That Bryce Harper sure can rake, can’t he?” With the trap successfully set, you would then drop this bomb on them: “… and Bryce Harper posted a 77 wRC+ over those 30 days!”

Good job, time traveler. You successfully terrified an innocent person about the future without mentioning the name Donald Trump or Hillary Clinton. But we seasoned veterans of the 2016 season are able to accept those facts as true. Over the past 30 days, Bryce Harper (.289 wOBA) and Ben Revere (.287 wOBA) have been equivalently awful for the Nationals and, yet, the team is on an offensive tear. As you might expect, it’s been necessary for a lot of different players to perform well in order to make up for Harper’s lack of production – Wilson Ramos and Daniel Murphy have hit well all season while Danny Espinosa and Jayson Werth have recently turned their early season struggles around – but the biggest contributor for the Nationals at the plate of late has been Anthony Rendon.

Through May 9th, Rendon had hit a dismal .211/.289/.297, a line which amounted to offensive production nearly 40% below league average. Coming off a disappointing and injury-plagued 2015 season, it was natural to start wondering whether the 2014 season which led to him finishing fifth place in MVP voting was a flash in the pan never to be seen again. But then, Rendon started hitting. He entered play last night with a .324/.411/.546 line since the cherry-picked date of May 9th. This offensive outburst has raised his full-season wRC+ to a perfectly respectable 107.

Although the May 9th dividing line is arbitrary, it does come close to splitting his season in half, with 142 of his plate appearance coming before this magical date and 128 coming after. Let’s keep using this convenient dividing line to help us take a look at a key change in Rendon’s approach — one which may help explain his recent offensive outburst.

Part of being good at, well, anything, is learning to maximize your strengths and compensate for your weaknesses. An incredibly basic heat map is all we need to begin to identify one of Rendon’s key strengths and one of his key weaknesses at the plate. Here is Rendon’s career batting average per pitch denoted by pitch location:

While batting average may be an imperfect metric, there is a crystal clear hot zone in Rendon’s map. He has clearly found more success on pitches located on the inner half of the plate and down in the zone than he has on pitches up and away. With that in mind, here are two more heat maps — in this case, depicting the pitch location on Rendon’s hits this season. This first map shows the pitch location of Rendon’s hits through our chosen date of May 9th:

That sure fits with the basic assumption we formed off the heat map. Not a single one of his hits over that time period was on a pitch located up and away. Of course that chart merely depicts the first five weeks of Rendon’s season and we’ve already established that he struggled during that time. Surely things have changed since he’s begun to heat up at the plate:

Then again, maybe not. Anthony Rendon has recorded 62 hits this season and every single one of them has been on pitches in the bottom left half of a diagonally-spliced strike zone. Clearly Rendon’s offensive production hasn’t turned around via an improved ability to get to pitches across the entire strike zone.

Remember when I said that success was about capitalizing on strengths and compensating for weaknesses? Rendon hasn’t found a way to overcome his weakness on pitches up and away, but he has found a way to minimize its impact. The following hea tmap shows Rendon’s swing rate on all pitches through May 9th:

Notice how he demonstrated a clear preference for swinging at pitches located in his sweet spot but that he also swung at pitches in parts of the zone where he’s been historically less successful. Now compare that to his swing-rate heat map since May 9th:

What was a noticeable inclination to swing at pitches in his hitting zone has transformed into an overwhelming tendency. Rendon has simultaneously become more aggressive on pitches in his zone and more passive on pitches outside of it. He’s essentially become the epitome of the old clichés about waiting for your pitch and refusing to swing at a pitcher’s pitch.

While demonstrating an increased focus on pitches down and in, Rendon has seen a real shift in his batted-ball trends. Prior to our select date, his batted-ball heat map suggests that he was hitting the ball to all parts of the outfield relatively evenly:

But ever since that date, he’s shown an increased tendency towards pulling the ball to left field:

Logically, this makes sense. Pitches down and in tend to be hit to the pull field, and hits to the opposite field occur on pitches away in the zone more often than not. Since Rendon is doing his best to ignore that the outside part of the zone exists, he’s in a good position to hit to the pull side. And, like most hitters, the pull side is where Rendon generates the most power. So far this season, his ISO to the pull field (.278) dwarfs his ISO up the middle (.113) and to the opposite field (.148). It comes as no surprise, then, that one of the biggest parts of Rendon’s recent offensive surge has been his power. Prior to May 9th he had a .086 ISO that was barely befitting a shortstop, let alone a corner infielder. Since May 9th, however, he’s posted a .222 ISO, which is infinitely more palatable from a middle-of-the-order third baseman.

By focusing on the area of the strike zone where he can do the most damage, Rendon has returned to being one of the better-hitting third basemen in the league. This turnaround was particularly important to the Nationals’ current success due to the fact that it coincided with the absence of a productive Bryce Harper. However, the fact that there’s currently a glaring hole in his approach could be a reason as to worry about the sustainability of his current success. If pitchers begin to consistently locate pitches up and away to Rendon, he’s going to need to find a new adjustment to succeed. Until that time comes, though, mashing pitches down and in is certainly doing the trick.