Source register
| Source | Status | Role here |
|---|---|---|
| Retrosheet | admitted | Primary open play-by-play, game, and historical backbone. Commercial use expressly permitted by its notice, with the attribution below reproduced verbatim. |
| Chadwick Bureau Register | admitted | Cross-provider player identity (ODC-By 1.0), captured at a pinned commit. |
| Lahman / SABR database | quarantined | Not used. Its current distribution's own license files (including a separately licensed Seamheads Negro-Leagues component) must be audited before any admission. |
| MLB Statcast / Baseball Savant | methodology only | Definitions and formulas are cited; no automated collection, no raw ingestion. MLB's terms prohibit automated scripts and derivative redistribution without written permission. |
| MLB Stats API | methodology only | Governed by a notice permitting only individual, non-commercial, non-bulk use. Not a dependency. |
| Sports Reference | no ingestion | Linked reference only; its terms prohibit scraped databases and competing tools. |
| FanGraphs · Baseball Prospectus · Sports Info Solutions | private comparators | Methodology references. Any owner-licensed exports stay in a private lane, never on public surfaces and never as training labels. |
Retrosheet attribution (verbatim, both current variants)
The information used here was obtained free of charge from and is copyrighted by Retrosheet. Interested parties may contact Retrosheet at 20 Sunset Rd., Newark, DE 19711.
The information used here was obtained free of charge from and is copyrighted by Retrosheet. Interested parties may contact Retrosheet at "www.retrosheet.org".
Retrosheet currently publishes both required statements (notice.txt and its download pages differ); this site reproduces both verbatim rather than choosing. Retrosheet data are subject to correction as new evidence arrives; our captures pin exact releases and corrections arrive only as new versioned captures.
Identity attribution
Identity data from the Chadwick Baseball Bureau Register, made available under the Open Data Commons Attribution License (ODC-By) v1.0.
Statcast measurement regimes
Modern tracking data are not one stable measurement system. When (and only when) a lawful admitted source exists, every tracking-era metric here will carry a regime flag: 2015 full-park Statcast · 2020 Hawk-Eye optical transition · 2023 high-frame-rate cameras and partial-season bat tracking · 2024 public bat speed · 2025 framing-model update · 2026 ABS coordinate and zone redefinition. Series that cross a regime boundary without a flag are treated as invalid.