Jacob Stockdale has not been included in Ulster’s matchday squad to face Cardiff in the United Rugby Championship at Parc Y Scarlets on Saturday (15:00 GMT).
The Ireland wing has been following World Rugby’s return-to-play protocols after he developed delayed concussion symptoms following last week’s Challenge Cup win over Stade Francais at Affidea Stadium.
The Irish province’s starting team for the meeting with Cardiff shows four changes from the side which defeated their French opponents in European competition.
Michael Lowry returns from an ankle injury to replace Stockdale at full-back, while Werner Kok is drafted in on the right wing.
Australia loose-head prop Angus Bell is named in the front row after being forced to withdraw from the starting team to face Stade Francais last week because of illness.
Charlie Irvine has overcome a calf injury and comes into the second row to partner captain Iain Henderson, with Harry Sheridan dropping to the replacements’ bench.
The match will see scrum-half Nathan Doak, who was selected in the Ireland squad this week for the forthcoming Six Nations, make his 100th appearance for Ulster.
Ulster and Cardiff both sit on 31 points in the upper echelons of the URC table, with the Welsh outfit having played one game more.
Cardiff secured a 29-26 victory over Richie Murphy’s side when the teams met in the pool stage of the Challenge Cup in December.
Ulster: Lowry; Baloucoune, Hume, McCloskey, Kok; Murphy, Doak; Bell, Stewart, O’Toole; Henderson (c), Irvine; McCann, Timoney, Ward.
Replacements: Herring, O’Sullivan, Wilson, Sheridan, Dalton, McKee, Flannery, Postlethwaite.