Posted By:
RobertSIs it a postcard or a smaller card?
If it's the professional Toronto team (and it sure looks like it), then it should have some players who were in the majors. One such guy was Jack Thoney who played from 1902 to 1911 in Cleveland, Boston, New York and elsewhere.
This in-action postcard features him on Opening Day in 1907 at Hanlon's Point in Toronto.

Sorry if the scan's a bit large...