Eggs a novice on at the cricket ground (4)
I believe the answer is:
oval
'the cricket ground' is the definition.
(London cricket ground)
'eggs a novice on' is the wordplay.
'eggs' becomes 'ova' (term for egg cells).
'a novice' becomes 'L' (as in a learner driver with L-plates on their car).
'on' means one lot of letters go next to another.
'ova'+'l'='OVAL'
'at' is the link.
(Other definitions for oval that I've seen before include "Curved shape" , "Squashed circle" , "Like eggs" , "Rounded like an egg" , "Surrey county cricket ground" .)