How Jarren Duran’s Swing Adjustments Have Made Him a Star in Boston

After a turbulent first two seasons at the big league level, Red Sox outfielder Jarren Duran seemed to put things together in 2023, hitting .295 with an OPS of .828 in 102 games before a broken toe ended his season. Despite a disappointing end, Duran’s 2023 was an exciting development for the Red Sox, who have been bullish on the speedy, physical left-handed hitting outfielder. Little did they know, Duran’s 2.5 fWAR season would be the appetizer for the main course that has been his 2024 breakout.

Through 100 games, Duran has already compiled 53 extra base hits on his way to a 4.3 fWAR. He has also made defensive improvements that have pushed his WAR totals into overdrive, which has already been well documented this season. But since making a mechanical adjustment in the batter’s box in mid-May, Duran has been one of the best hitters in baseball.

Swing Adjustments

Going back through the video, I was able to pinpoint May 15th as the first game that Duran re-introduced the leg kick that he utilized in his 2021 breakout in Triple-A, but had later ditched as he struggled to find consistency at the big league level.

Similar to the James Wood breakdown, the idea of adding a leg kick being conducive to making more contact seems almost counter-intuitive, as most hitters want to simplify. Much like James Wood, Duran is an elite athlete in the box, and reintroducing the leg kick he utilized in 2021 allowed him to tap back into that athleticism.

His short, quick stride left him looking rushed at the plate, unable to pattern his moves with much rhythm. Even with a simpler move, the later load made it difficult for Duran to get into his back side and create tension as his load became one rapid move, taking him out of his back side almost as soon as he got there.

Duran starts his new move earlier, reaching the peak of his leg kick before the pitcher even releases the baseball, consistently starting his load right as the pitcher breaks his hands. A slower-building, rhythmic load allows Duran to coil into his back side and stay there. As he lowers his lead leg, he continues to coil into his back side, helping combat a premature forward move while creating more hip/shoulder separation and tension, like a rubber-band.

There’s quite a few positive outcomes from these mechanical findings from Duran, and once again, they are quite similar to the positive results that Wood found when he made a nearly identical change, just with a bit less dramatic of a leg kick.

Higher Exit Velocities and Launch Angles

The uptick in power is two-fold. Utilizing the lower half more effectively not only allows a hitter to generate more force, but it also helps them create a more desirable angle to the baseball swing path-wise, as a premature forward move can cause a steeper path. The shift in both impact and overall batted ball consistency are undeniable.

Hitting the ball harder and in the air more frequently will always bode well for production, which is why he has hit almost as many home runs in his 56 games since the swing change (11) than he had in his 235 MLB games prior (14).

Starting earlier and being in a better position prior to launch paired with the nearly 2 mile-per-hour leap in bat speed has helped Duran do much more damage on pitches on the inner half. A 1.8 MPH increase in bat speed may not sound like a ton, but according to Baseball Savant’s bat tracking leaderboard, it’s the difference between MLB’s 47th percentile and 78th percentile.

Nine of Duran’s 11 home runs since May 15th have come on pitches on the inner half, contributing to what is nearly a 400 point difference in OPS. With a path more conducive to entering the zone earlier and staying there longer, he has been less pull-dependent in inside pitches and elevate more consistently.

Similarly, Duran’s production against velocity improved drastically, as his bat speed helps him catch up, but so does getting his launch position earlier. Over his last 57 games, he is slashing .337/.396/.518 against fastballs 93 MPH and above. He has performed fairly well against velocity since the beginning of 2023, however only a handful of hitters in baseball have been more impressive against heaters since the middle of May.

His ground ball rate on inside pitches dropped by 10% while his pull rate was slashed from by 47% to 32%. He’s still pulling the ball enough, but he’s getting much more bang for his buck when he does, exemplified by his 22 extra base hits over his last 56 games compared to just 7 in his 43 games prior. A bat that stays in the zone for a longer distance while traveling through it at a higher velocity looks like this.

Pair the wider contact margin with more athleticism and mobility in the box, and improvements against secondary pitches should follow as well.

The side by side below is a great example of how much more adjustable Duran can be. Now that he is more engaged with their back side, he is able to go down and get the slider and backspin it to center field at 111 MPH. Once weight shifts forward, lower half adjustability and overall feel for the barrel tends to wane, which can also result in it lagging behind him.

The difference in production against secondaries is striking with the batted ball data to back it up. He’s able to stay behind the baseball longer with confidence that he can turn around harder stuff inside while also creating more leverage in his swing on softer stuff that may have been a rollover flare off of the end of the bat in the past.

This truly is a breakout in every sense of the word for Duran. Sometimes an adjustment can rectify one thing, but leave a hitter more exposed in another area. Oftentimes, athletic and powerful hitters are encouraged to simplify things in the box, which can be helpful in theory, but can also make them more mechanical and minimize their edge that cannot be taught.

There’s a difference between movement and wasted movement, especially when a hitter starts their load far earlier. The aforementioned James Wood is a prime example, but so is Jurickson Profar this year (that piece is coming soon) and 2024 Giants first rounder James Tibbs, who slashed his strikeout rate in college from 31% to 11% after making a similar adjustment.

Even with those recent success stories, it’s not something all hitters can just shift to. If everyone could start their load as early as possible, most would, but the challenge is that there is now more time for the mechanics to go awry. There’s a level of body control, athleticism and hip mobility required that can make it a difficult move for the average hitter. If the move is not repeated consistently, more timing issues can follow as well as mechanical breakdowns which is why it was such a surprise to see Duran make the change in-season.

Beyond the damage that the 27-year-old is now doing at the plate, he is managing his at-bats better overall, as he has evolved into the most complete version we have seen of him. He has slashed his chase rate to the lowest figure of his career, while straying from his propensity to swing at the first pitch, something he did nearly 10% above league average last year. With that, his strikeout rate has dropped by 3% on the season with 1.2% increase in free passes.

The cherry on top has been Duran’s elite defense. Much like his hitting ability, Duran has had all of the tools to be a top-notch center fielder, but struggled to “finish plays” in the words of his manager Alex Cora. That has been far from the issue this year, sitting tied with Harrison Bader for 9th among outfielders with 7 Outs Above Average.

In terms of fWAR, Jarren Duran checks in at second among center fielders at 4.3, trailing only Aaron Judge and is tied with Bryce Harper for the 9th highest total among all position players. Of course, Duran will need to produce like this a bit longer before he is discussed with some of the game’s best, but all indications point towards Duran becoming the Red Sox latest homegrown star, just on a slightly less traditional path.