Good morning everyone! I was referred here by r/history and I have a question for you all. I am looking for some primary sources about my chosen subject. Yes, I am writing a paper. No, I'm not asking for anyone to do my homework. I am just at a loss for any quality and scholarly primary sources for my chosen topic and am looking to be pointed in the right direction.

Here's what I have. My research question is as follows:
Despite early push back or segregation of Irish immigrants, how did early Irish baseball players gain their acceptance and become some of the best to ever play?

My thesis statement, albeit not that strong, is as follows:

The acceptance of early Irish immigrants into the game of baseball demonstrates that their discrimination by the mostly Protestant Anglo population in the New England areas in which they settled in was a combination of their lack of meaningful skills, lack of education, and their religious views (Catholic), contrary to the argument of many scholars that suggest it was the fact that they were taking unskilled, labor jobs at lower wages than the already established workforce.

I have plenty of scholarly secondary sources, but am lacking any real primary sources. For those that don't know, a primary source provides direct or firsthand evidence about an event, object, person, or work of art. So, for example letters from players or Irish immigrants from 1880 - 1900 or photographs from that era. I am really at an impasse here. I have been searching for two months and can't find anything. If anyone knows of any scholarly sites or collections that might relate to my subject, I would be most grateful. Again, I am just looking to be pointed in the right direction or even just given suggestions that I may have not thought of at this point.

Mods, if you feel that this is inappropriate, please feel free to remove it. I am just looking for a little bit of help or direction from a new set of "eyes".