At first, clubs always pursue several international players (4)
I believe the answer is:
caps
'international players' is the definition.
(eg an internationally capped footballer)
'at first clubs always pursue several' is the wordplay.
'at first' says to take the initial letters.
The initial letters of 'clubs always pursue several' is 'CAPS'.
(Other definitions for caps that I've seen before include "Headgear for international players" , "Headgear for internationals" , "Coverings for heads or bottles" , "Crowns" , "is better" .)