Joe DiMaggio league baseball
 

Anyone know when these were made?? Guessing it has to be around 1937-38??

They weren't in the 1937 catalog, but are listed in the 1941 catalog (shown below). I don't have scans/photos of the intervening years, so not sure if 1941 was the first year for them, but that at least gets you in the ballpark.

Edit to add: The Spalding logo used on your ball is an earlier one than the ball pictured on the catalog page I posted. Your logo was used through 1940 on their ONL balls, so I suspect it's at least 1 year earlier than the 1941 ball pictured in the catalog.

There have been several sold in the past that have 1938 Yankee team signatures. They are the same stamping.

http://catalog.scpauctions.com/1938-...-lot28064.aspx

http://www.lelands.com/auction/Aucti...igned-Baseball