Coming in short of runs, preparing to play (6,2)
I believe the answer is:
'preparing to play' is the definition.
'coming in short of runs' is the wordplay.
'coming in' becomes 'turning up' (turn up can mean to appear or come in).
'short of' indicates named letters should be taken away.
'runs' becomes 'r' (cricket abbreviation).
'turningup' with 'r' removed is 'TUNING UP'.