There's a good possibility that it was originally larger, and was cut down (or folded) to fit the frame. I suspect you could tell a lot more by removing it from the frame and examining it.
Here is a Yankee Stadium "Philadelphia" example with very similar style and lettering. Yours could have been from a similar time frame... perhaps yours is a bit earlier than this Heritage example. Link below...
https://sports.ha.com/itm/baseball-c.../50013-56369.s
Also, if you look towards the top of the Heritage Listing, you'll see other teams' flags from that series. Only the White Sox has the team name, versus the City name (presumably because there are 2 Chicago Teams).