Cubs historical sleuthing: Ron Santo and Roberto Clemente edition

Photo by Focus on Sport/Getty ImagesGetty Images supplied the following information with this photo (again, I fixed a couple of typos):

Outfielder Roberto Clemente #21 of the Pittsburgh Pirates dives back into first base safe against the Chicago Cubs during a Major League Baseball game circa 1970 at Wrigley Field in Chicago, Illinois. Clemente played for the Pirates from 1955-72.

Right away, I’m sure you can tell me what’s wrong with that information. It’s clearly not first base, because that’s Ron Santo (No. 10) in the photo. So this play has to be at third base, not first base, as the number of career games played at first base by Santo as a Cub was zero. (Santo did play first base three…