Hardly ever runs relay badly (6)
I believe the answer is:
rarely
'hardly ever' is the definition.
(I've seen this before)
'runs relay badly' is the wordplay.
'runs' becomes 'r' (cricket abbreviation).
'badly' indicates anagramming the letters (letters in the wrong order).
'relay' anagrammed gives 'arely'.
'r'+'arely'='RARELY'
(Other definitions for rarely that I've seen before include "Not done or occurring very often" , "Gas used in fluorescent signs" , "once in a blue moon" , "Very occasionally" , "when hundred-to-one horse wins?" .)