April 20, 2021

The Seamheads Negro Leagues DB: A Brief Introduction

December 28, 2020 by · 4 Comments 

In the wake of the recent announcement about MLB’s recognition of the Negro leagues, we prepared the following brief introduction to our work here.

The Seamheads Negro Leagues Database is an in-progress statistical encyclopedia covering Black professional baseball players, teams, and leagues during the era of segregation. Our work was specifically commended by Commissioner of Baseball Rob Manfred when he announced that the Negro leagues would be recognized as major leagues. Bryant Gumbel of HBO’s Real Sports pronounced our database to be “the most authoritative record of Negro league statistics ever assembled.”

In addition to games between Black major league teams (including postseason series and All-Star games), we also offer statistics for exhibition games between Black teams and white major and minor league teams. And, as Black American players often played in Latin American leagues, and Black players from Latin America played in the Negro leagues in the U.S., we cover Cuban and Mexican baseball of the era, and plan to cover Puerto Rico, the Dominican Republic, and Venezuela in the future.

Currently we have at least some data for every season in the United States from 1886 through 1948, as well as more than 20 Cuban seasons from 1899/1900 through 1927/28 and several Mexican seasons in the 1940s. We are always uncovering and adding new seasons, leagues, games, and other information to our database, so it is worth checking back frequently to see what’s new.

Our database (with the exception of the Mexican League statistics) is built from the game level up, using box scores, newspaper articles, and scoresheets. Currently we do not make use of published year-end statistics or standings—everything is verified from contemporary accounts of individual games.

Another core principle of the database is that both sides of every game are represented. Consequently many white major and minor leaguers are present in the database, so it’s possible to see how Babe Ruth or Christy Mathewson fared against Black or Cuban competition. (White major and minor leaguers might also appear because they played in the Cuban or Mexican leagues.)

For a number of leagues and seasons, we still need to add fielding and complete pitching statistics (e.g. home runs allowed by pitchers), as well as hit by pitch for batters. These seasons include: 1924 ECL, 1925 NNL & ECL, 1927 NNL & ECL, 1929 NNL, 1930 NNL, 1932 NSL, 1939-42 NNL & NAL, 1944-46 NNL & NAL. We also need to add fielding statistics for 5 of 6 ECL teams in 1923.


Postseason series and All-Star games are presented as separate “leagues,” as are exhibition games against white major and minor leaguers.

A blank space does not indicate a zero; it means insufficient or missing data. In general, we do not have enough data for batters’ strikeouts and caught stealing in Negro league games; there are exceptions for some postseason series and All-Star games. However, both categories are available for many Cuban League seasons, and batters’ strikeouts were recorded in Mexican League statistics.

The default display for player pages shows all stints combined for any given year; that is, it shows one line for each season of a player’s career. If a player appeared for more than one team, or his team appeared in the playoffs or World Series, the default display adds his statistics together. (This means, incidentally, that zeros will sometimes appear for columns that are actually blank.) If you click the “Show Individual Stints” button it will separate out a player’s stints within a given season.

The per-162-game figures given after career totals on every player page adjust for missing and incomplete statistics. We use 162 games to enable cross-era comparisons to major league players.

UPDATE 1/18/2021 Also keep in mind that at its core the database covers games between teams we’ve defined as Black major league teams—that is, teams roughly comparable in quality to the teams in organized Negro leagues, 1920-1948. It does not (yet) cover games against white semipro and amateur teams, lower-level white minor league teams, college teams, and teams we’ve defined as Black minor league teams. Especially prior to 1920 and the advent of organized Negro leagues such games took up large parts of Black teams’ schedules—so the games counted here generally represent only a small part of each team’s season.


4 Responses to “The Seamheads Negro Leagues DB: A Brief Introduction”
  1. Dirk Durstein says:

    Congratulations on the accolades. The database reflects the painstaking efforts of so many people, working with original sources. I understand why you would not necessarily want to focus on the years after 1948, as black players began to appear for a few major league teams, and in the minor leagues. But I am curious how black leagues continued, in some fashion, up until around 1960. And occasionally, players would appear in the minors or even MLB, who had played on vestigial Negro League teams. So, will there be any effort to assemble statistics for those latter years? I get it that the quality of play deteriorated quickly, as the better players were scooped up by MLB teams. But – a particular interest of mine – there were plenty of Negro League veterans who never got a chance in the Major Leagues, and who kept playing for black teams well into the 1950’s. I would think – perhaps I am naive – that these stats would be more accessible, by virtue of being more recent? (I am well aware of the practice of assigning those with labor-intensive ideas the task of doing the work, and I am recently retired….)

  2. Gary Ashwill says:

    Thanks! Yes, we intend to include post-1948 statistics here eventually, though at this point MLB has put their stopping point at 1948. Unfortunately fewer and fewer box scores were published in the 1950s, and while official statistics exist for some seasons, they can be pretty limited. We’ll do our best.

  3. James Olson says:

    Hello! First off, I want to congratulate you on a job well done. I am a frequent visitor of your site and have been for some time. I had an idea I thought maybe you could put out there, since I have a very small voice in the baseball community. With the news that Negro Leaguers will now finally be recognized statistically alongside their white counterparts, I think it would be an excellent addition to add a WAR/PA or WAR/Game statistic to Baseball-Reference. I thought you might have a say in this when Baseball Reference incorporates your work into its database.

    My reasoning is that the Negro Leaguers played less league games and thus didn’t accrue as much WAR. Furthermore, my understanding is that you and others have roughly 75% of all box scores on-hand, with more being uncovered as time passes. On a leaderboard, Negro Leaguers won’t appear alongside the likes of Ruth or Cobb in total WAR. But in a WAR/PA or WAR/Game leaderboard, they would. With rate requirements not games played but 3.1 plate appearances per team game played, we’d be able to see a 1932 WAR/PA or WAR/Game leaderboard with Ruth, Gehrig, Foxx, Charleston, Gibson, and Stearnes. I think it would be an appropriate way to honor the Negro Leaguers in their respective context. Anyways, I tried getting this idea across to the hard workers at http://sports-reference.com but to no avail. I thought you would maybe appreciate the idea and work to its fruition better than I. You’ve been really good for the baseball community as of late and I’m a big fan.

  4. Gary Ashwill says:

    Hi James, thank you! It’s possible something like what you mention will appear at Baseball-Reference at some point, though we can’t say for sure. In the meantime of course on our site we have WAR per 162 games: http://www.seamheads.com/NegroLgs/history.php?tab=metrics_162

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