Start with an invented line
Suppose a batter has three hits in ten at-bats, with no walks, hit-by-pitches or sacrifice flies. The batting average is 3/10=.300. In this simplified line, OBP is also 3/10=.300.
Now add one officially recorded sacrifice fly. The batter still has three hits in ten at-bats, so batting average remains .300. For OBP, the denominator becomes eleven while the numerator remains three:3/11 is about .273. The rates separate even though the hit total has not changed.
A useful out is still not reaching base
A sacrifice fly can help a runner score while the batter is put out. The team contribution and the batter’s on-base outcome are different questions. Lower OBP after that play does not mean the run was removed or that the scorer forgot the contribution.
Do not assign sacrifice-fly status merely because a fly ball was hit with a runner on third. Use the official scoring label. The scoring conditions determine whether SF enters the record, and a replay cut before the runner’s action may not show enough to make that decision.
Check the denominator before comparing screens
If a live graphic shows .300 batting average and a later statistics page shows .273 OBP, first check that the column labels, time range and underlying figures match. The numbers may both be correct. Different denominators can explain the apparent disagreement without a data error.
This worked example intentionally omits other events to isolate the sacrifice fly’s effect. In a real season line, walks and hit-by-pitches also enter the standard OBP calculation, while other scoring categories have their own treatment. Keep the official counts rather than trying to derive every rate from a single broadcast summary. For an archive note, write H, AB, BB, HBP and SF beside the displayed rates. That makes the calculation reproducible and prevents a helpful scoring out from being mistaken for an extra official at-bat.
A one-for-three batting line can similarly coexist with four completed turns if one turn was an SF. The extra completed opportunity belongs in the appropriate statistical field.
Related questions
Are the examples actual player results?
No. The figures are invented to show the calculation.
Sources and scope
Scope notes distinguish published documentation, supplied information and editorial methods. They do not report a hands-on service test.
- MLB sacrifice fly — SF excluded from AB and included for OBP effect
- MLB statistical field definitions — Published OBP formula
- MLB official 2019 rules archive — Historical rulebook corroboration of scoring structure; current glossary supplies present definitions
