Work slicing sausages for game participants (4,6)

'game participants' is the definition.
(horses used in the game of polo)

'work slicing sausages' is the wordplay.
'work' becomes 'op' (common abbreviation for 'opus').
'slicing' indicates putting letters inside (some letters slice into others).
'sausages' becomes 'polonies' (polony is a kind of sausage).
'op' put into 'polonies' is 'POLO PONIES'.

'for' is the link.