Cipriani will compete with Leicester's Toby Flood for the fly-half shirt while Abendanon, who has been in eye-catching form for Bath, will provide extra competiton at full-back.
Hopley contrasted Williams' 12-month ban with the less severe punishments handed out to South Africa flanker Schalk Burger for eye-gouging and to former Bath lock Justin Harrison for admitting three drug-related charges.