Marc Valdes: 21 Career Home Runs Allowed

Much of the data on Baseball-Reference.com's Home Run Logs comes from the Tattersall/McConnell Home Run Log, a database of all homers hit in the major leagues since 1876. This project was begun in the 1940's by John C. Tattersall and was continued after Tattersall's death in 1981 by Bob McConnell, one of SABR's original 16 members. David Vincent, another SABR member, has since assumed the leadership of the project. Baseball-Reference.com has licensed this remarkable database from the Society for American Baseball Research. All credit for the data therein goes to the intrepid researchers who digitized this data from archival sources.

For years from 1954 to 2009, RetroSheet play-by-play data has been used whenever the home run occurred in a game for which we have complete play-by-play data.

There are a handful of cases where the home run logs totals do not agree with the totals on our player pages. We are working to reconcile all of those differences, but believe that in all cases the Home Run Encyclopedia is correct.