Munster coach Declan Kidney and his Ulster counterpart Mark McCall have been unable to confirm their starting line-ups, injuries the most obvious culprit, ahead of tonight's Magners Celtic League game at Ravenhill. Morning fitness tests are expected to clear the muddy waters of the selection process.
David Humphreys, who has agreed a final one-year contract with the province, must prove his fitness, with prop Simon Best also charged with the same task. The presence or otherwise of Humphreys has ramifications for the rest of the three-quarter line.
If he's absent then Paddy Wallace would switch from inside centre, Andrew Trimble would join Paul Steinmetz in midfield and Paul McKenzie would start on the wing. Humphreys' presence would see everyone move out a place with Trimble on the wing and McKenzie dropping to the bench.
Simon Best, a second-half replacement in Rome where he picked up an injury, is hoping to make the bench; his absence would mean a place for Declan Fitzpatrick in the squad. Ryan Caldwell starts his first game for Ulster this season while Ireland under-20 Grand Slam captain David Pollock is on the bench.
Kidney faces a couple of selection posers with regard to the replacements. A vacancy has been left among the forwards and that could be filled by former Ireland under-21 international secondrow Shane O'Connor. Rugby league recruit Brian Carney is vying with Ireland under-20 Grand Slam winner Keith Earls for a place on the bench.
Ulster approach this match one point behind leaders Leinster and determined to take advantage against a Munster side shorn of their busy international contingent who played in the recent Six Nations Championship.
Hooker Jerry Flannery is the only current international in the visitors' pack and Kidney has understandably opted not to flog his test contingent seven days ahead of their Heineken European Cup quarter-final against Lllanelli at Stradey Park.
But Munster still field pretty much a first-choice three-quarter line, even allowing for the positioning of Barry Murphy on the wing. Shaun Payne, Anthony Horgan and John Kelly probably won't be available for next week's game either.
Murphy might return to centre for the Llanelli game opening up a chance for Tomas O'Leary or Carney to play on the wing. The Munster pack has an experienced backbone in Flannery, Chris Wyatt and captain Alan Quinlan and contains the promising Donnacha Ryan, a good competitor.
They face a tough evening against an Ulster eight for whom Roger Wilson has been outstanding. Stephen Ferris is a powerful ball-carrier. The front five are mobile and their set-piece play is generally excellent.
Whatever permutation is eventually arrived at in the backline, there'll be plenty of potency and on paper Ulster look to have an edge at halfback. But the contest up front should prove decisive.
Ulster have the stronger, more settled side available and should be driven by the greater urgency in this particular competition. The vocal home support will fuel that desire. The subplots regarding individual confrontations will interest Ireland coach Eddie O'Sullivan as he marshals his plans ahead of the summer tour to Argentina and the Churchill Cup.
Munster will relish the thought of being written off but the home side are intent on retaining their Celtic League crown and securing a number one seeding when next season's European Cup draw comes around.
ULSTER: B Cunningham; T Bowe; P Steinmetz /Andrew Trimble, P Wallace/Paul Steinmetz, P McKenzie /Andrew Trimble; D Humphreys/Paddy Wallace, I Boss; J Fitzpatrick, R Best; B Young; J Harrison (capt); R Caldwell; S Ferris; K Dawson, R Wilson. Replacements: P Shields, S Best/D Fitzpatrick, T Barker, D Pollock, K Campbell, P McKenzie/AN Other, A Maxwell.
MUNSTER: C Cullen; B Murphy, L Mafi, T Halstead, I Dowling; E Hickey, T O'Leary; E McGovern, J Flannery, T Buckley; D Ryan, C Wyatt; A Quinlan (capt), T McGann, J O'Sullivan. Replacements: T Ryan, F Sheahan, M Melbourne, AN Other, B O'Meara, J Manning, B Carney or K Earls.
Referee: A Rolland (Ireland).
Last time they met:Munster 21 Ulster 13.
Leading points scorers:Ulster - David Humphreys 124. Munster - Jeremy Manning 68.
Leading try scorers:Ulster - A Trimble, T Bowe, B Cunningham, P Steinmetz 4 each.
Munster -Lifeimi Mafi, Tomas O'Leary, David Wallace 2 each.
Verdict:Ulster to win.
Ulster v Munster
Ravenhill, 7.30
On TV: Setanta Sports