This brings us to Herb Pennock. Pennock pitched 11 seasons with the Yankees, going 162-90 with a 3.54 ERA. He pitched in nine seasons with the Red Sox over two stints going 62-59 with a 3.67 ERA. He was on two World Champion teams with the Red Sox and was a decent pitcher, but not a star.
However, let's look at his Hall of Fame plaque:
It is often stated that the reason Pennock is in the Hall of Fame is due to his work with the Yankees, but this plaque seems to show him with the Red Sox. It is not completely obvious, but it looks like the bottom of a "B" can be seen just above the bill of his cap. It certainly does not look like an "NY" and the only other team he played for was the Philadelphia A's.
Then there is this picture, which looks a lot like it might have been the picture, or at least from the same set of pictures as the one used to create the plaque.
Notice the piping on the uniform shirt and the hat and the facial features. This looks like it proves that the cap Pennock is wearing on his Hall of Fame plaque is a Red Sox cap.