With year out, struggling player's form drops (5)
I believe the answer is:
pearl
'form drops' is the definition.
(pearl can mean to form drops like a pearl)
I don't understand how the remainder of the clue works.
(Other definitions for pearl that I've seen before include "Much loved and valued person" , "Gem from oyster" , "Gem from a bivalve" , "Precious gem" , "Object of great worth" .)