There are fears Conor Murray could miss Munster's opening two games in this season's Champions Cup.
The Ireland scrum-half is dealing with a persistent neck injury.
It was expected that Murray would miss the opening two to three games of the Pro 14 season, but that break could be extended to October.
Munster's Pro 14 campaign begins against the Cheetahs on Saturday, while their European seasons starts with games against Exeter Chiefs and Gloucester.
The province's young guns lost their final pre-season game on Friday 12-0 to Exeter.
Munster boss, Johann van Graan, said after the game that his options for Saturday are limited.
He said: "Currently I don’t have a lot of options available to pick, currently we only have three wings training with us. No, if you call it a headache it can go both ways.
“I thought Liam Coombes really did well. I thought Shane, again, really did well. But it is such a long season, you are going to need or use more than 50 guys. We used more than 50 guys last season, so you have to give these players opportunity to play and this team (that faced Exeter) will definitely not go out for the next part of the season as a team because such a lot of guys are yet to come back.
“If you quickly go through it, James Cronin, Rhys Marshall, Niall Scannell, Stephen Archer, John Ryan, Tadhg Beirne, Peter O’Mahony, CJ Stander, Chris Cloete, Conor Oliver, Jack O’Donoghue — that is only in the forwards — that still need to come into the team.
“Then you have Conor Murray, Joey Carbery, Tyler Bleyendaal, Chris Farrell, Jaco Taute, Keith Earls, Andrew Conway, Ronan O’Mahony, and I may have left one out. I don’t want to use it as an excuse."
