It looks like Weaver was a right handed hitter when he came up, but learned to switch hit for the 1913 season. According to
https://www.clearbuck.com/about-george- ... ck-weaver/ ...Buck ended the 1912 season with a paltry .224 batting average and .915 fielding percentage. Knowing his position on the Chicago White Sox roster was not secure, he spent the entire off-season learning to become a switch hitter. Since all his cards are post-1913, they should all be switch hitters.