Rugby:A bout of tummy bug, injury and the IRFU Player Welfare system has combined to give Munster and Ulster an entirely different look this weekend.

In total 12 players are unavailable for Ulster and 17 for Munster as the teams meet in the Pro 12 tomorrow evening in Belfast (KO: 7.05pm).

Because of the four day turnaround, Ulster coach Brian McLaughlin has coached two separate teams for the games with the line-up for Ravenhill having a more familiar look to it.

"It's a huge game for it, it's at Ravenhill and it's against Munster. When the fixture list came out we were not very happy with the fact that we had a four day turnaround but we just have to manage the scheduling as best we can." said McLaughlin.

“We want to put our best team out on the pitch as often as we possibly can, but Irish Management Programme looks after the Internationals and we have to look after the rest of the players as well so we took the decision, and it was not taken lightly, to run two separate squads for two games."

Injury to Nevin Spence (ankle), sustained during Ulster's trip to Aironi sees Ian Whitten recalled to the starting side for the first time since Ulster faced Treviso at Ravenhill on 7th October, and he will partner Darren Cave in the centre, while Stefan Terblanche will make his first starting appearance for Ulster since arriving at the beginning of December.

The South African, brought in as cover for the injured Jared Payne on a short-term contract has come off the bench twice for Ulster so far, against Aironi in Rounds three and four of the Heineken Cup.

Willie Faloon makes a return to the back row alongside Pedrie Wannenburg and Chris Henry while Callum Black, Ali Birch, Chris Farrell and Peter Nelson, who all made their Ulster debuts against Leinster, are named amongst the replacements.

"It's a big game and I don't have to say a lot to lift the guys for it, we all know that the games between Irish provinces are the big games for the team,” said Ulster's South African Captain Johann Muller.

“We know what's coming, we know Munster are an outstanding team but we're at Ravenhill, we have a great record there and we want to keep it that way.”

“Munster's strength is their consistency - it doesn't matter what tournament they play in, they're always there or thereabouts. They are a team that never says die, that's the Munster that I've got to know over the last 18 months or so, they are always there and if they don't win they'll always get a losing bonus point. Consistency is a key for them, and as a squad it's something we can learn from."

Munster's unavailable list is considerable. The injured include David Wallace (knee); Troy Smith (knee); Felix Jones (foot); Jerry Flannery (calf); Doug Howlett (achilles); Darragh Hurley (back); Mike Sherry (ankle); Peter O'Mahony (jaw); Denis Leamy (hip), Declan Cusack (shoulder); Sean Scanlon (shoulder), while the IRFU policy keeps Paul O'Connell, Donncha O'Callaghan, Donncha Ryan, Conor Murray, Ronan O'Gara and Keith Earls out of the match.

Mick O'Driscoll, Ian Keatley and Luke O'Dea are the trio who remain in the line-up, while the likes of Danny Barnes and Niall Ronan, after 10 and 11 starts respectively are given a well earned rest.

"Given the very short turnaround and looking at their selection for the Leinster game last week, Ulster has clearly identified this game as the priority." said second row and captain O'Driscoll.

"Understandable really, they're at home, no side likes to lose at their own ground. So I think it sets out very clearly the task we face. But these are the sort of games you want to be judged on. We've a lot of young lads going there tomorrow. Some for the first time. It's going to be very testing and very interesting."

Ulster:A D'Arcy; C Gilroy, D Cave, I Whitten, S Terblanche; I Humphreys, R Pienaar; P McAllister, A Kyriacou, J Afoa, J Muller (Captain), D Tuohy, P Wannenburg, W Faloon, C Henry Replacements: N Brady, C Black, A Macklin, L Stevenson, A Birch, P Marshall, C Farrell, P Nelson

Munster: D Hurley; L O'Dea, T Gleeson, L Mafi, J Murphy; I Keatley, D Williams; W du Preez, D Varley, S Archer; I Nagle, M O'Driscoll capt; Dave O'Callaghan, T O'Donnell, J Coughlan. Replacements: D Fogarty, M Horan, J Ryan, B Holland, P Butler, T O'Leary, S Deasy, W Chambers.