Please see below link to SABR article on J. L. Wilkinson. The main point that seals the deal for Dan B. in my eyes is the mention that Wilkinson kept three male players on an otherwise all-female team and if you look at the postcard, there are three male players pictured. Too much of a coincidence for me. As far as facial resemblance, I won't comment on that one way or the other as it is not a real photo postcard but a commercially printed one and the image is not clear enough to make a determination. I also don't know if we have another image of Wilkinson dating to the 1908-10 time period that we could compare it to.
http://sabr.org/bioproj/person/db4ae51d