Down-at-heel actor being brought initially into cast (6)
I believe the answer is:
shabby
'down-at-heel' is the definition.
(thesaurus)
'actor being brought initially into cast' is the wordplay.
'initially' suggests taking the first letters.
'into' means one lot of letters goes inside another.
'cast' becomes 'shy' (I've seen this before**).
The initial letters of 'actor being brought' is 'abb'.
'abb' placed within 'shy' is 'SHABBY'.
(Other definitions for shabby that I've seen before include "Worn and run-down, like clothes" , "Dingy; dishonourable" , "Badly worn" , "Dingy - dirty" , "in worn and dirty clothes" .)