The reason for the slightly unusual shape is due to the fact that this was built as a multipurpose stadium for baseball and football. While baseball hugs both the lines, football stadiums usually have one of two long grandstands that cover the length of the grid iron. Often we see "J" shaped stadiums when a pre-WWII stadium is designed to host dual sports. (See Watertown South Dakaota’s Watertown Stadium, Breese Field in Madison WI, Bradner Stadium in Olean NY and Greensboro NC's War Memorial Stadium for other examples of this type of configuration.