It's often replaced on sporting grounds (5)
I believe the answer is:
divot
'grounds' is the definition.
The answer and definition can be both natural objects as well as being singular nouns.
Maybe there's an association between them I don't understand?
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for divot that I've seen before include "Displaced grass" , "Piece of turf dug out of the fairway by a golf shot" , "Clump of turf for a golfer to replace" , "Bit of turf cut out by golf club" , "Golfer's dislodged turf" .)