one more filter on roundabout

one more filter on roundabout

YASQ - I make roundabout image menu, and i want add effect on central box. SMt like grayscale/jumping on HOVER. (to indicate for user that this is clickable link)
As far as i can see, easing addon works only wih 'clik'', not hover.
Is there a simple option for smt like that? Or it need another plugin? Existed maybe?