The Shift Ban’s
Hidden Ledger
When MLB outlawed the infield shift in 2023, it didn’t just move fielders — it quietly transferred hundreds of runs from defenses to left-handed hitters. Here is the accounting, entry by entry.
The switch that flipped overnight
In 2022, defenses stacked three infielders on one side of second base for about a third of every ball put in play. On Opening Day 2023, the rule made it illegal — and usage didn’t taper off. It went straight to zero. That clean on/off is what makes the ban a rare thing in baseball: a controlled experiment run on the entire league at once.
Reading the ledger
The shift only ever guarded one thing well: a left-handed hitter’s pulled ground ball, rolled straight into a stacked right side. Strip the league down to just those balls and the ban’s effect jumps out.
But 2023 changed other things too — a pitch clock, bigger bases. To isolate the shift, we use right-handed hitters, who were almost never shifted, as a control: whatever moved for them is not the shift. What moved for lefties beyond that is its fingerprint.
| Group | Run value/BIP 2022 | Run value/BIP 2023 | BABIP 2022 | BABIP 2023 |
|---|---|---|---|---|
| Left-handed (treated) | −.117 | −.093 | .168 | .213 |
| Right-handed (control) | −.065 | −.067 | .229 | .240 |
The dashed marker is where lefties would have landed if the only thing acting on them were the same forces that moved the control. The gap from there up to the red point is the shift ban, and nothing else.
returned to left-handed offense in a single season — on pulled grounders alone.
95% CI 285 – 584 runs · ≈ +562 hits · +.034 BABIP net of control
| Credit — offense | Debit — defense | |
|---|---|---|
| Runs | +435 | −435 |
| Hits on pulled grounders | +562 | −562 |
| BABIP, pulled grounders | +.034 | −.034 |
Every run credited to a hitter is a run debited from a defense that used to be standing in the right place.
The teams that shifted most, lost most
If the shift was really doing the work, the clubs that leaned on it hardest should have felt its removal most. They did. Plot each team’s 2022 shift rate against how much more its left-handed opponents suddenly hit on pulled grounders in 2023, and the line slopes up — r = +.45. Houston shifted on nearly four of every five lefty balls in play and gave back the most.
The trend is the story, not any single dot — each team defends only ~500 such balls a year, so individual points are noisy. Read the slope.
| Team | Shift rate | BABIP-allowed rise |
|---|---|---|
| HOU | 79% | +.092 |
| MIN | 68% | +.093 |
| BOS | 68% | +.093 |
| LAD | 68% | +.053 |
| DET | 64% | +.017 |
| CWS | 63% | +.024 |
| LAA | 61% | +.114 |
| WSH | 59% | +.030 |
| SEA | 59% | +.073 |
| TOR | 58% | +.058 |
| TEX | 58% | +.074 |
| CHC | 57% | +.039 |
| MIA | 55% | +.083 |
| SF | 54% | −.010 |
| CIN | 53% | +.028 |
| ATH | 51% | +.054 |
| SD | 51% | +.052 |
| PIT | 50% | +.038 |
| NYY | 49% | +.025 |
| AZ | 46% | +.083 |
| NYM | 46% | −.013 |
| KC | 46% | +.036 |
| BAL | 44% | +.015 |
| CLE | 43% | +.049 |
| PHI | 43% | +.048 |
| MIL | 43% | +.010 |
| STL | 43% | +.031 |
| TB | 42% | +.063 |
| ATL | 36% | +.007 |
| COL | 26% | +.043 |
Two ways to cash in
Hitters didn’t all collect the windfall the same way. Some never changed a thing — the exact same swing, watching grounders that used to die in the shift now sneak through (Seager, Happ, Harper, Soto). Others read the new rules and started pulling more, now that the right side was open (Crawford, Greene, Brandon Lowe).
The two responses turn out to be unrelated: how much a hitter changed his spray tells you nothing about how big his windfall was — r +.07. You could profit by adapting, or by standing perfectly still.
Horizontal axis: did he change his approach? Vertical axis: did it pay off? The flat cloud says those are two independent questions. n = 96 lefties with ≥150 balls in play and ≥40 pulled grounders in both seasons.
| Hitter | Role | Change in pull rate | BABIP windfall |
|---|---|---|---|
| Bryce Harper | beneficiary | +.007 | +.102 |
| Corey Seager | beneficiary | −.009 | +.112 |
| JP Crawford | adapter | +.113 | +.080 |
| Ian Happ | beneficiary | −.002 | +.119 |
| Brandon Lowe | adapter | +.098 | +.222 |
| Juan Soto | beneficiary | +.018 | +.120 |
| Riley Greene | adapter | +.110 | +.022 |
| Anthony Santander | — | −.031 | +.201 |
| MJ Melendez | — | −.034 | +.161 |
| Yoan Moncada | — | +.085 | +.153 |
| Geraldo Perdomo | — | +.016 | +.146 |
| Kyle Tucker | — | +.013 | +.131 |
| Max Kepler | — | −.007 | +.122 |
| Shohei Ohtani | — | +.050 | +.118 |
| Mike Moustakas | — | −.044 | +.108 |