Clue: Former Kent player always up to conserve energy (5)
Answer: REEVE
Explanation: Former Kent player always up to conserve energy (5)
EVER ("always", up) to conserve E (energy) 
*I used to know more about cricket than I do now, having quit the game a decade ago, but the only Reeve I am aware of is Dermot Reeve, who didn't play for Kent. If it is another Reeve, then it is likely to be someone obscure.