Williams – cousin of New Zealand World Cup winner Sonny Bill Williams – has scored 13 tries in 67 appearances for Ulster during a four-year spell.

"With the short turn around and following a very physical game against Munster, we obviously see some changes in the side this week."

Ireland duo Paddy Jackson and Darren Cave have been included in Ulster's squad for tomorrow night's Guinness PRO12 tie against Cardiff Blues at Kingspan Stadium.