Ulster and Ireland backrow Stephen Ferris has been ruled out of action for between four and six weeks with a knee injury.

Ferris injured the knee in Ireland's second Test in Argentina during the summer but was passed fit to travel to France with the World Cup squad.

Despite playing the role of the onlooker in France, Ferris's injury flared up again when he returned and the Ulster medical staff have advised he be rested.

Mark McCall is currently preparing his side for tomorrow's opening European Cup pool game against Gloucester at Ravenhill.

The earliest he is expected back is by round three or four of the competition when Ulster face Ospreys back-to-back.

McCall is already without backrow Neil McMillan but has been boosted by the positive prognosis for Kieron Dawson, whose leg injury is not as serious as first feared.

McCall is expected to name his tam later today.