Wee-hours guard guy (13)
I believe the answer is:
nightwatchman
(Other definitions for nightwatchman that I've seen before include "Earlier than expected arrival at the batting crease?" , "Inferior batsman" , "Someone promoted up the ordinary batting order when a wicket falls close to the end of the day's play" , "one who may take guard close to stumps?" , "Poorer batsman sent in early, towards the end of play" .)