The Wales wing has missed the last two games due to a rotator cuff strain sustained during the victory over Treviso a fortnight ago.

While Williams may be fit to return for the clash with Munster on January 9, Holley is wary of re-introducing him to competitive action.

"We have given him an injection, some rest and hopefully that will be sufficient for the European games (on 17 and 24 January).

"At the moment our physio is telling me he could be available for Munster.

"We are taking a sensible view not to rush him back with some big games coming up. Whether it will need further exploration we don't know yet."