Possible Clues:

• Cricketer who takes guard late?
• I'm expected to handle late deliveries
• Relatively inexpert batsman sent in to bat before close of play
• Batsman who is vigilant in the dark?
• Job in the dark for an astronomer?
• Tail-ender sent in to bat when a wicket falls close to the end of a day’s play
• After dark, timekeeper making late arrival at Lord's?
• Security guard for the hours of darkness
• Guard man going in late at Old Trafford?
• Cricketer charged with securing his wicket (to protect 'better' players) until close of play