[prewarsports]

My guess (and this is just a guess) would be that this was a mock-up for some type of publication or advertising done by the print shop and then presented to the publisher so they could see it in print form before heading to mass production which was very expensive. Nearly every newspaper archive I have been to that predates WWII has things that look just like this but done "in house" by the printers at the newspaper. I have all sorts of paper scraps done on thick cardboard or blank backed paper that were mocked up by artists and then sent up to the publishers so they could see the finished product before they made thousands of them at high costs. These things I find are almost always from the 1920's (about when this was done) and look VERY similar in style but less card-like.

For example, that calendar above would have had an artist mock-up the player photos in the boxes and at various stages of publication they could have been printed in strips (before the calendar part was added) and sent to the customer for review. Those strips, if they existed today, would certainly look like a strip card set, but would just be part of making the calendar. Most of these of course would be discarded once the finished product was done, but in the case of newspapers they sometimes were kept in case they wanted to re-use them down the road.

The red lines in the middle and non-conformity in size are indicators to me that this was not really intended to be baseball cards, but some type of other publication that was in the process of being completed.

Just a guess.