PAUL O'CONNELL is a major concern for Ireland's tour to New Zealand next month, with the Munster captain due to see a specialist this week after sustaining a serious knee injury in Saturday night's win over Ulster in Thomond Park.
Munster have not yet ruled him out of Friday's Pro12 semi-final clash with Ospreys but say he is unlikely to feature.
"He was assisted off the field so that's a good indicator, not a good sign," said coach Tony McGahan.
An injury to the same knee, suffered against France, cut short O'Connell's Six Nations campaign before he returned for Munster in time for the Heineken Cup quarter-final against Ulster.
"It's the same knee, but the injury he had before was more of a cut, an infection in there -- this one is more of a twist, so we will have to wait and see," added McGahan.
Hooker Damien Varley sprained his ankle and also looks set to miss the trip to Swansea, but Ronan O'Gara should be available for the semi-final along with Ian Keatley, who withdrew from Saturday's match with a knock.
Munster got on top from the outset and ran in five tries to secure a semi-final joust against the only other side to lift this title three times. However, McGahan admitted that improvement would be required if they are to continue their bid to become the first side to retain the title.
"I was delighted with the players, the way they reacted following the (Heineken Cup) quarter-final exit," he said. "We would maybe have liked to finish off a few more things but that was more eagerness than anything, so we'll see it as a step forward.
"It certainly wasn't about revenge because we had an opportunity to win a quarter-final and didn't take it."
Ulster, who head away on a brief camp to Portugal to start their preparations for the Heineken Cup final on Saturday week, have concerns about a knock to the head suffered by Ian Humphreys, but backs coach Neil Doak was hopeful it was not serious.
Ulster fielded an under-strength side for their final league game of the season and can now turn their full attention to the Twickenham clash with Leinster, but Doak admitted that game may have been on players' minds on Saturday.
"When you're playing a European Cup final in two weeks, some guys are bound to be looking beyond some things, maybe we weren't as fired up as possibly we could have been," said Doak.
Munster, with Lifeimi Mafi superb in his final Thomond Park outing, struck early with Simon Zebo crossing for his 12th try of the season seven minutes in and they led 17-3 at the break after Peter O'Mahony finished a good move.
Munster were on top up front but Ulster's promising Irish U-20 Iain Henderson drove through for a fine try after Mike Sherry got Munster's third.
But Munster finished strongly and after Mick O'Driscoll was given a standing ovation from the 12,500 crowd before his retirement, Stephen Archer secured Munster's fifth try bonus point of the campaign four minutes from time.
They added a fifth in the final play of the night when Tommy O'Donnell burst free. The impressive Scott Deasy, a late replacement for Ian Keatley, slotted three of the conversions while Declan Cusack, who is being let go, landed one in his only appearance of the season.
Munster -- F Jones; J Murphy, I Dineen (K Earls 58), L Mafi, S Zebo (D Cusack 77); S Deasy, C Murray (T O'Leary 55); W du Preez (D Kilcoyne, 65), M Sherry (D Varley 50, Sherry 78), BJ Botha (S Archer, 67); M O'Driscoll (D O'Callaghan 70), P O'Connell (P Butler 55); D Ryan, T O'Donnell, P O'Mahony.
Ulster -- A D'Arcy (C Gilroy 64); A Trimble (I Humphreys 50,), N Spence, I Whitten, C Cochrane; P Jackson, P Marshall (B McIlroy 60); P McAllister (T Court 12), N Brady (N Annett, 67), D Fitzpatrick (C Black 55); L Stevenson, D Tuohy; I Henderson, W Faloon (A Birch 47), R Diack (M McComish 55).
Ref -- A Rolland (IRFU).