Worry about rugby player’s Rastafarian hairstyle (10)
I believe the answer is:
dreadlocks
'rastafarian hairstyle' is the definition.
(I've seen this before)
'worry about rugby player's' is the wordplay.
'worry about' becomes 'dread'.
'rugby player's' becomes 'lock's' (second row of a scrum).
'dread'+'locks'='DREADLOCKS'
(Other definitions for dreadlocks that I've seen before include "Rastafarian hairstyle" , "They're pretty hairy!" , "great shock" , "Houdini didn't" , "Matted thatch" .)