Baseball’s $4 Million Swing Secret: Shorter Arc, Not Slower Bat Speed, Study Finds

The Two-Strike Adjustment MLB Hitters Should Be Making, Study Finds

Baseball teams spend millions every offseason hunting the smallest edges. A new study published in The American Statistician has put a price tag on one: roughly $4 million, found in how batters adjust their swing mechanics when the count goes against them.

Scott Powers of Rice University and Ronald Yurko of Carnegie Mellon University found it tucked inside the league’s own tracking data, though reaching that conclusion first required working past a number that appeared to say the exact opposite.

MLB began releasing pitch-by-pitch bat tracking data in 2024, reporting bat speed and swing length on every single swing. On the surface, the data seemed to imply something strange: swings that result in solid contact are, on average, slightly faster than a batter’s typical swing. If taken at face value, that would mean batters should always swing as hard as possible. Something was off.

MLB’s New Bat Speed Data Hides a Costly Measurement Problem

Bat speed and swing length are both recorded at the exact moment the bat makes contact. That creates a statistical trap. A batter who swings too early connects near the tail end of the swing’s arc, when the bat is already decelerating. A batter who reads the pitch perfectly makes contact at peak speed. Faster measured bat speed often just reflects better timing, not a harder swing. Without accounting for that, the raw numbers tell a misleading story.

Pitch recognition compounds the problem further. When a batter gears up for a fastball and gets a curveball instead, he typically makes a last-second mid-swing adjustment that kills bat speed and scrambles his mechanics. That same tweak makes contact far less likely. A slower observed swing can mean either a deliberate, controlled two-strike approach or a panicked mid-swing adjustment. Off raw numbers alone, those two situations are impossible to tell apart.

To separate intent from accident, the researchers drew on more than 685,000 pitches from the 2024 regular season. They isolated a subset of about 32,000 swings that produced clean, solid contact on primary fastballs, situations the researchers treated as the clearest window into what each hitter was actually trying to do. Working from that baseline, they built statistical models to estimate each player’s likely intended bat speed and swing length, stripped of the distortions caused by timing and pitch-guessing.

Shorter Swing Arc, Not Slower Bat Speed, Is the Winning Two-Strike Formula

Once pitch recognition was removed from the equation, the data told a different story. As strikes pile up, batters intentionally pare down their swings. With each additional strike, the average big leaguer drops bat speed by about 1 mph and trims swing length by less than a quarter of an inch. Batters differ considerably in how far they take those adjustments, and those differences drive the $4 million gap.

Batters who throttle back their bat speed more per strike do make contact more often in one- and two-strike counts. That much is intuitive. But they pay a price: less power when they do connect. Bat speed’s effect on contact rate is more than three times larger than swing length’s effect, meaning that sacrificing speed costs a batter far more than simply compressing the physical arc of the swing.

That asymmetry is where the value lives. Shortening the swing arc while preserving bat speed turns out to boost contact without giving back anything in power. Per the study, it appears to be the cleanest two-strike adjustment captured by these metrics: more contact, without the power penalty that comes from slowing the bat.

Oakland A’s Alumni Lead Baseball’s Most Valuable Two-Strike Approaches

At the top of the approach rankings: Matt Chapman, Matt Olson, and Mark Canha. All three spent five or more early-career seasons together with the Oakland Athletics, a coincidence the authors flag as interesting without claiming Oakland caused the shared approach. In the study’s model, the gap between the best and worst approaches works out to roughly four runs per 500 trips to the plate, which the authors translate to about $4 million in free-agent market value.

Near the bottom: Santiago Espinal and Jake McCarthy. Trea Turner, widely regarded as one of the game’s most accomplished hitters, also ranks toward the lower end, which is worth keeping in mind: approach is just one small contributor to overall offensive production, and the spread of raw talent is far wider than any edge gained from a smarter two-strike plan.

Metrics released by MLB in 2025, including attack angle, attack direction, and swing tilt, are already giving researchers more to work with, though the paper notes they still describe what happens at contact rather than the full path of a swing.

Raw bat speed alone tells an incomplete story, and taking it at face value could lead teams to miss a meaningful edge. Batters generating the most two-strike value are not simply swinging harder or softer. They are making one specific adjustment: compressing the arc while keeping the speed intact. In the study’s model, that approach is worth about $4 million in free-agent value, and any team that can develop it deliberately has a meaningful head start.

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Disclaimer: This article is based on peer-reviewed research published in an academic journal. Study findings reflect statistical modeling and the authors’ analysis, and should not be interpreted as direct measurements of player value or team salary outcomes.

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