Ward-Smith was also injured just before this year's Six Nations

The number eight was forced off in their Heineken Cup win over Harlequins and could be out for two months.

"If it is a clean break, he is likely to be out for six weeks but if it's splintered, it could be eight weeks," said Bristol coach Richard Hill.

England open up their Six Nations campaign against Wales on 2 February.

In a further setback for Bristol, England World Cup hooker Mark Regan picked up a shoulder injury in the same game.

Regan was substituted just after half time and was replaced by try-scorer David Blaney, who was himself stretchered off in injury time with a suspected broken ankle.

It is the second season running that Ward-Smith has suffered an injury setback in the build-up to the Six Nations.

Earlier this year, the 29-year-old suffered a dislocated kneecap and a ruptured patella playing for his club against Northampton when an England call-up beckoned.

He had recovered enough to work with England's World Cup training squad in the summer but failed to prove he had reached the required fitness level to be included in the final party that travelled to France.

Ward-Smith missed Bristol's opening game of the season against Leicester but returned to the team for the clash with Sale on 23 September.

"It's very unlucky for him," added Hill. "Last year, before he was badly injured, he was out for six weeks with a thumb problem."