Players keeping article introducing a card game (7)
I believe the answer is:
canasta
'card game' is the definition.
(canasta is a kind of card game)
'players keeping article introducing a' is the wordplay.
'players' becomes 'cast' (I've seen this before**).
'keeping' means one lot of letters goes inside another.
'article' becomes 'an' (indefinite article).
'introducing' says to put letters next to each other.
'cast' placed around 'an' is 'canast'.
'canast'+'a'='CANASTA'
(Other definitions for canasta that I've seen before include "Card game like rummy" , "Game played with two packs of cards and jokers" , "Decorated with artificial jewels" , "Card game -- as an act (anag)" , "Card game of the rummy family" .)