At Sportsman Park in St. Louis Missouri, one player stands behind the catcher's plate while another player stands on third base as he looks outward towards the outfield. There are two players standing behind the the third baseman in foul territory. One of these players stands about 15 feet behind the third baseman and the other player stands way farther back behind these two players. There is another player who is standing in the grass in between home plate and third base.
This is the correct position for the infielders to follow when there is a baserunner on second base and a fly ball is hit to right field. The baserunner on second base may attempt to steal the base depending on how deep the baseball is hit to right field. If the baserunner steals, then the shortstop should cover third base and the third baseman should stand behind to back him up in case the right fielder overthrows the base. The pitcher is backing up the third baseman and stands the farthest back. Meanwhile, the first baseman has moved to around the pitcher's mound just in case of any emergency that might occur. Since the ball is going to be thrown to third base anyway, the first baseman can be more useful by standing near the pitcher's mound than he would be if he chose to remain on third base.
Good condition;
This digital image is made from two separate digital scans; one scan of the lantern slide (reflective); one scan of the image (transparency); the two images were then combined in Photoshop to create the final image.
Lantern slide from the Leslie Mann baseball instruction course, "The Fundamentals of Baseball"