Stance Shifters: Part 2

Using Statcast data, we can track which of the four aspects of a hitter’s batting stance moved and by how much across each month of the season. In this piece, I wanted to go a step further with some of the names from part one and layer in bat tracking data and batted ball tendencies to see whether the stance changes translated into a measurable swing change.

Fernando Tatis Jr.

He has one of the highest tinkering scores, which has come primarily from opening his angle month-on-month. From a relatively neutral 10 degrees open in April, this had increased by 25 degrees in June; the severity of this change is evident in the side-by-side comparison image. This increased by a further 10 degrees by August, and it seems to have settled at around 44 degrees.

Following his departure from New York to Baltimore, Alonso had also started the year pretty slowly. Coming out of August, he had become one of the hottest hitters in baseball. From a setup point of view, while his shift was not as severe as the 25-degree shift from Tatis, but he was the only bat to move directionally in all four setup metrics. A couple of these are very marginal and would have almost no impact, but it’s interesting to get an overall picture of change in setup.

Alonso, following from this slow start, widened his stance considerably, while simultaneously getting closer to the plate and further up in the box with a marginally more closed-off stance angle. I think the directional shift of these movements might be more salient here than with someone like Tatis, given that it is more incremental and multi-faceted. With a hitter of Alonso’s experience, being able to slowly move towards a certain feel or setup that can help him is important. Noting his experience, it also shows a willingness to adapt and a certain maturity to slowly move in one direction in many ways, paired with the experience of not doing too much too quickly.

Following those changes, Alonso’s Hard% climbed from 43.4% in April to 58.4% in August as his base widened, with his two highest hard-hit months coming on his widest stance. HR/FB followed a similar trajectory, jumping from 12.1% to over 30% in the final two months. The wider base didn’t change his swing length, which stayed flat all season, but it did change the quality of his contact.

Chase Meidroth

In much the same vein as Tatis, Meidroth has opened up his stance significantly in order to increase his ability to pull the ball. These cases are very similar, with both sitting in the top right corner of the chart having found the same solution to the same problem. While I am no hitting coach, there is obviously something mechanical about opening the stance that can help players address a problem pulling the ball.  His attack angle climbed from 8 degrees to 15 degrees as he opened, turning a flat swing into one with real loft. His attack direction shifted from 5 degrees opposite field in April to 1 degree pull by August, and his Pull% followed, rising from 37.6% to 51.3%; while this has regressed in September, he has still maintained a respectable offensive output. Once he pushed past 30 degrees in July, his attack angle continued to climb, and FB% jumped to 48.6% by September.

From a fantasy perspective, Meidroth is becoming a much more productive hitter in the second half after struggling to make much of a mark earlier in the season. A post-break OPS close to .800 is valuable if he can make that the norm rather than returning to the .700 range he posted early in the year. If he can sustain that level of production, he should provide considerably more fantasy value.

Steven Kwan

Kwan seemed to be fading out of all fantasy relevance in 2026, with a wRC+ at one point of 26. Kwan was one of the worst hitters in baseball and offered little value, with his fantasy value dropping down to -$13.9 at his lowest point midway through the year. To his credit (and anyone who may have rostered or started him), he made adjustments and has since put up a wRC+ of 151 in the second half.

Kwan’s improvement is notable precisely because almost nothing about his underlying power profile changed. Bat speed remained between 61 and 63 mph throughout the season, while Hard% never escaped the 15 to 24% range. His xwOBA, however, climbed from .281 in April to .396 in July. In fact, the improvement in output does not even correspond directly to his gradual shift at the plate. Getting slowly deeper in the box, he has seemingly made the simple adjustment of giving himself a fraction more time. And thus, Kwan rejuvenated his season.

As a contact-oriented bat, the correlation between his batting average and his overall offensive production is clear. While that may seem obvious for a hitter like Kwan who has a clear ceiling at this point in his career, establishing that floor is critical. An adjustment as simple as moving back in the box helped turn his season around, allowing him to get bat to ball more consistently. And although results did not come right away, Kwan kept creeping back and was a different hitter in the second half as a result

How much difference these shifts in hitters’ stance can have on their production is difficult to judge. But shifting setups can obviously have an impact for certain hitters, and how they change their stance can also impact their mechanics. Patterns like opening the stance angle to increase the ability to pull the ball, or widening the stance to increase power, could provide templates for the future.