Dan Leavy and Jacob Stockdale will remain on the sidelines.
Dan Leavy has been ruled out for the rest of the season after undergoing knee surgery.
The Leinster flanker had only returned from a 19-month absence in October.
It’s believed Leavy’s latest procedure was an elective one, and he’ll return in the summer.
Meanwhile, Jacob Stockdale appears unlikely to be fit in time for Ireland’s Six Nations clash with Italy.
Ulster have confirmed the winger remains sidelined with a knee injury.
Stockdale sustained the injury in the festive win over Munster in the Pro 14.