Letter on the right is from Eddie Collins to pitcher Otey Clark discussing draft status.
I've posted this one before. Here is a Mel Ott and others signed Belgium note. The players/writer were on a USO tour during WW2, more specifically during the Battle of the Bulge. Purchased it from the son of the guy who originally obtained the signatures.
Photo caption: Baseball icons (far side of table, left to right): Frankie Frisch, manager of the Pittsburgh Pirates; Mel Ott, player-manager of the New York Giants; Bucky Walters, pitcher for the Cincinnati Reds and Dutch Leonard, pitcher for the Washington Senators share Christmas dinner with soldiers of the 90th Infantry Division at Cattenom, France - December 25, 1944 (U.S. Army Signal Corps, Courtesy National Archives).