Player on pitch, one hanging on to gate (12)
I believe the answer is:
wicketkeeper
'player on pitch one' is the definition.
The definition suggests a singular noun which matches the answer.
'hanging on to gate' is the wordplay.
'hanging on' becomes 'keeper' (I can't justify this - if you can you should give a lot more credence to this answer).
'to' says to put letters next to each other (I've seen this in other clues).
'gate' becomes 'wicket gate' (wicket is a kind of gate).
'keeper' put after 'wicket' is 'WICKETKEEPER'.
Can you help me to learn more?
(Other definitions for wicketkeeper that I've seen before include "Cricketer" , "Stumper" , "The person behind the stumps" , "Close fielder" , "Fielder behind stumps" .)