Paul O'Connell and Keith Earls are both on the road to recovery but will not be available for the start of Munster's new season.
O'Connell has been given the all-clear to return to lifting weights this week as he steps up his return from the arm injury he picked-up during the Lions Tour.
The second-row is now hoping to be back in first-team action a couple of weeks before the start of the Heineken Cup group stages in October.
Meanwhile, Earls says he is still recovering from the shoulder injury that ruled him out of the end of last season as well as Ireland's summer tour of North America.
The centre has been taking part in training all summer, but has not begun contact work with the rest of the squad and will not be available for the first 2 or 3 rounds of the Pro-12.
©INPHO/Billy Stickland