Baseball's Musial (4)
I believe the answer is:
stan
'baseball's musial' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for stan that I've seen before include "Eminem hit; man's name" , "Laurel perhaps" , "Laurel and Hardy, . . . . and Ollie" , "One of the comic duo" , "Ollie's partner" .)