Balls first Reardon and then Selby hold — these, perhaps (4)
I believe the answer is:
reds
But I can't explain it at all! Could you help me understand?
(Other definitions for reds that I've seen before include "Tidies up" , "Scarlet and crimson, say" , "Colourful communists" , "Colours for communists" , "Left-wingers" .)