1910 phillies unpublished photo, debut

[billyb]

I have been searching for teams with a nickname that started with a "p", but concentrating on a possible letter on the hat as a "d" or a "B".
When I first looked at the uniform, along with the hat, the 1910 Phillies had an away and a home hat. One was white with the letter, the other was dark, but no letter appeared on the hat. Identical to the photo. So I thought, maybe they were the Phillys, but with a practice uniform, but as Mark pointed out, they did not have collars after 1908. Beside, why would an umpire be there for practice.
So, not the Phillys.

I will go back and concentrate on the letter on the hat as possibly being a "P".

Again, the only clue was, the photographer, was living in Flint, Michigan at the time, of this photo, as his stamp is on the back, with a Flint, Michigan location, but no date given.