Johnny Sexton and Robbie Henshaw have been ruled out of Irelandâ€™s Autumn Nations Cup game against England on Saturday because of injury.
Fly-half Sexton, 35, has had a scan on a hamstring injury that he sustained in Fridayâ€™s win over Wales.
Centre Henshaw, 27, injured an abductor muscle in the same game and will also miss the Twickenham contest.
Iain Henderson and Jacob Stockdale could feature this weekend after being late withdrawals from the Wales match.
The Irish Rugby Football Union said that lock Henderson would return to training on Monday while his Ulster team-mate Stockdale will continue to get treatment on his calf injury in the hope that he may be able to resume sessions later this week.
Ulster fly-half Billy Burns will follow the return-to-play protocols this week after having to leave the field for a head injury assessment during his first cap.
Scrum-half Conor Murray switched to fly-half for the closing 15 minutes of Fridayâ€™s game and Ireland coach Andy Farrell said afterwards that the Munster man was a “genuine option” in the number 10 role.