Initially, stars of Chelsea can expect reasonable game (6)
I believe the answer is:
soccer
'game' is the definition.
(I've seen this before)
'initially stars of chelsea can expect reasonable' is the wordplay.
'initially' says to take the initial letters.
The first letters of 'stars of chelsea can expect reasonable' is 'SOCCER'.
(Other definitions for soccer that I've seen before include "Informally, game" , "Roy Keane's game" , "The beautiful game?" , "Football for Americans?" , "popular game" .)