The home and away factor to this year's Guinness Interprovincials means it's less of a sprint and more of a gallop. Nonetheless, none of the four participants can afford to start off too slowly and were Leinster to lose to Munster in Dooradoyle this evening they would find themselves eight or nine points off the pace.

The pressure, then, is marginally more intense on the holders than it is on the home side. All the more so after their thumping home defeat to Ulster a week ago. Combined with Munster's admittedly laboured win over Connacht, Munster go into this game as strong favourites at 3/1 on.

Leinster can hardly be as bad as they were last week, when injuries and a disrupted preparation meant it was their first full outing of the season. Rather like a racehorse making its seasonal debut, they're bound to come on for the run.

Munster, too, will assuredly get better, though after their two-match tour of Wales, their improvement is unlikely to be so marked.

Mindful of the favourite's tag, it's a point Declan Kidney accepts. "I'm not sure they'd had any games and I'm sure the run-out against Ulster will have been a huge help for them. Also, as champions, I expect them to come out all guns blazing."

A couple of other factors have shifted the balance as well. The incomparable Rhys Ellison is out of the Munster equation and Trevor Brennan has been added to the Leinster conundrum. Leinster have also stiffened their midfield with the tough-tackling Martin Ridge and, alongside Brennan and Victor Costello, Pat Ward's call-up makes for an altogether beefier Leinster backrow.

The more one makes of the Brennan factor, the less likely it is to have a bearing on the game - that's the nature of things. Nevertheless, the Leinster blind-side flanker will certainly be closely scrutinised and will severely need to curb his innate aggressiveness.

Herein lies the rub, for on the one hand Brennan is expected to be aggressive and abrasive. It's what his coaches, his fans and his fellow Irish players love about him (once they're not playing against him, or come to think of it, even training against him).

However, after his recent adverse attention, more than ever Brennan cannot overstep the mark. One recalls an exchange of fisticuffs in the corresponding fixture last year, when Brennan seemed to be taking on four Munster forwards with the Leinster cavalry not exactly riding to the rescue. He can ill afford a repeat, yet he's not much use to Leinster if he plays like a clawless pussycat. It's a tough balancing act.

Psychologically, Brennan's recall may well galvanise his teammates. Given a greater sense of unity and benefiting from a few rockets from Mike Ruddock during the week, one would expect them to put it up to Munster.

Their pick-and-go, driving forward game looked potentially effective against Ulster, and will presumably be more so when they cut out the handling errors, penalties and resulting turnovers.

A more settled Munster side (retaining nine from last year's game, compared to six for Leinster) have a bit more experience and power to them. But they were blowing pretty hard towards the end against Connacht. They seem to miss the third link in the dynamic Shannon back-row chain, Alan Quinlan, and there are question marks about the fitness of the tight five.

The Irish forwards on duty in South Africa were later back to training than their teammates, so Peter Clohessy, Mick Galwey and Anthony Foley will not be at optimum fitness level. One also suspects they've still to hit on their best forward unit and it's surprising that Des Clohessy hasn't broken through yet.

Munster remain something of an enigma. "When the scoring opportunities come, I'd like to see us actually putting them away and, again, get closer to playing for 80 minutes," admits Kidney.

Two years ago, Munster won a veritable feast by 45-40, whereas a year ago in Cork they outkicked Leinster by 15-12. "Somewhere in between," as Kidney predicts, looks a safe bet. "The incentive to score tries wasn't there last year, while then home and away series should also lend itself to more tries," he reasons.

Even so, neither pack has an out-and-out flyer in their ranks, pointing to a fairly muscular forward battle, and there are further clues which suggest the wings won't be seeing too much ball, at least not until well into the game.

The deep-lying Alan McGowan is still primarily a kicking out-half rather than a mover of the line, and Leinster are clearly gearing themselves more for midfield trench warfare than an expansive encounter with the selection of Ridge. Against this, Munster have opted for Brian Walsh as the replacement for Ellison, with Michael Lynch moving to inside centre.

Other options were Cian Mahony as a straight swap or shifting Killian Keane to centre, with Ronan O'Gara coming in at out-half. Here, Keane's superior kicking game and defence in the pivotal position probably held sway, with Walsh's big left foot adding to the equation.

One would expect most of the aerial stuff to be directed in behind John McWeeney than the comparatively secure Girvan Dempsey, a converted full-back. By comparison, the Munster back-three of Dominic Crotty (who counter-attacked more like old last week), John Lacey (who patrols the line well as well as being one of the best finishers around) and Anthony Horgan look a more reliable bet defensively and offensively.

It may well be closer than recent form suggests. Leinster should be mentally and physically stronger. They oughtn't to be lacking in the set-pieces and have the muscle to meet Munster head on across the gain line. And there's no Rhys Ellison.

But when the crunch times come, the Munster pack still look to have a bit more nous about them, while behind them Munster look to have a more potent running threat in Brian O'Meara, a better kicking game and marginally more variation.

Munster: D Crotty; J Lacey, B Walsh, M Lynch, A Horgan; K Keane, B O'Meara; I Murray, M McDermott, P Clohessy, M Galwey (capt), S Leahy, U O'Callaghan, A Foley, E Halvey. Replacements - Cian Mahony, J Hayes, T Tierney, F Sheahan, R O'Gara, D Clohessy, D Wallace.

Leinster: K Nowlan; J McWeeney, S Horgan, M Ridge, G Dempsey; A McGowan, D O'Mahony; E Byrne, S Byrne, A McKeen, P Holden, G Fulcher (capt), T Brennan, V Costello, P Ward. Replacements - H Hurley, P Smyth, H Kos, C Brownlie, D Hegarty, R Murphy, B Carey.

Referee: Alan Watson (Ulster).