1963 Fleer Baseball Set

Hey group,

This post is a combination of an observation, a logic deduction, and a
couple related questions.

The observation is that the 1963 Fleer Baseball set is sorted first by
the league name, then by the team city name, then by the player's last
name. But there's an exception (or anomaly) to this rule, and that is
with the Willie Mays card. Instead of being near the very end of the
set along with the other San Francisco Giants, he's at #5 and squeezed
in between the Baltimore Orioles and the Boston Red Sox.

It's fairly easy to deduce that an American League player (most likely
from Baltimore or Boston) was dropped from the set, and Mays was moved
into the #5 slot to fill the vacancy. Fleer probably found this
method more economically advantageous to deal with than renumbering
most of the set.

The questions I have are these: Which player was dropped from the
set, thereby necessitating the change? Why was he dropped from the
set?

Thanks!

Ron