living in a tree

[Greg Pulliam]

White Sox announcers John Rooney and Ed Farmer tonight noted that
ballplayers will say "He's living in a tree" about someone who is
going through a great fielding streak, gobbling up every ball
anywhere near them.  Rooney and Farmer were mystified as to the
metaphorical origin of the phrase--I would assume the ballplayers are
likening the streaking player to a squirrel, but of course I could be
wrong.  Anybody got any other ideas?

Greg Pulliam