Kinda thought that was a Giants cap, but couldn't tell for sure.
Taking it as fact that it is a Giants player, then, here's the charm image
presented quite inexpertly (but repeatedly!) alongside pics of some other
late 1940s-1951 Giants (plus Freddie Fitzsimmons, last a Giant in 1937,
and of course a pitcher, but previously suggested as a candidate)...
We know who we'd vote for, and we're 50.1% confident in our choice.