A game held in Sale, usually (2,1,4)
I believe the answer is:
as a rule
'usually' is the definition.
(thesaurus)
'a game held in sale' is the wordplay.
'game' becomes 'ru' (rugby union).
'held in' indicates putting letters inside.
'ru' placed within 'sale' is 'sarule'.
'a'+'sarule'='AS A RULE'
(Other definitions for as a rule that I've seen before include "none straighter" , "how one might take a calibrated rod" , "Usually, in general" , "Usually, in the normal course" , "In most cases" .)