Munster coach Alan Gaffney tonight called for clarification on Heineken Cup qualification rules ahead of Saturday's crunch clash against Gloucester in Limerick.
Even if they beat the Zurich Premiership leaders, Munster could still finish third in Pool Two and miss out on a prized last-eight place.
The six group winners and two best runners-up will progress, but Gaffney has queried the tournament definition of 'runner-up'.
Heineken Cup handbook competition rules refer to best-placed runners-up', but do not state that a team cannot go through from third place.
A potential three-way tie in Munster's pool means that Munster, Gloucester and Perpignan could finish the weekend on eight points, provided that Munster beat Gloucester and Perpignan defeat Italian side Viadana.
"I still cannot see that if you're in a very difficult pool, the pool that we are in, that if we won four games and still achieve eight points and are equal to any of the other teams who run second in their pool and we still score more tries than them, why shouldn't we qualify as number seven or number eight?
"I don't understand as to why not, so we need clarification on it," Gaffney said.
"We are not making any legal issue of it at this time, but no doubt the branch (Munster) will make the appropriate enquiries within ERC (European Rugby Cup Limited) and see where things lie.
"It's just something we need clarification on. We just believe that's the way things are. If it pans out in our direction, that is not what we expect, but believe that's the way it should be," he told the BBC.
An ERC spokesman said that runner-up meant runner-up, and the two non-group winners going through to the quarter-finals would be sides finishing second in their respective pools.
If Munster finish third they are likely to have a better record than all other sides, apart from the six pool winners and team filling second place in their group.
Meanwhile, Gaffney delayed announcing his side for the Gloucester clash, instead he named a 24-man squad.
Gaffney will name his final line-up on Friday morning to give several players optimum recovery time from injuries they picked up against Perpignan.
Gaffney said: "A few of the boys picked up knocks in France and although I'd be hopeful that they'll be okay, I don't see any point in rushing things at this stage.
"We'll have a look at them all tomorrow in Cork and be in a better position then to assess the situation."
Munster squad:Backs: Jeremy Staunton, Killian Keane, John Kelly, Jason Holland, Mike Mullins, Mossie Lawlor, Colm McMahon, Dom Malone, Mike Prendergast, Peter Stringer, Ronan O'Gara.
Forwards:Marcus Horan, Martin Cahill, James Blaney, Frank Sheahan, John Hayes, Mick O'Driscoll, Mick Galwey, Donncha O'Callaghan, Denis Leamy, Eddie Halvey, Jim Williams, Alan Quinlan, Anthony Foley.