Trying to discern whether Joe Schmidt or Declan Kidney is sporting a broader grin this weekend is a moot point. Suffice to say they share a delight in welcoming the return of medium to long-term injury victims Brian O’Driscoll, Rob Kearney and Luke Fitzgerald to competitive fare when they line out for Leinster in Edinburgh tonight.

There will be a certain anxiety too as match intensity can not be replicated in training. Psychologically the triumvirate will benefit from every collision, every twist and turn from which they emerge unscathed, their confidence levels growing exponentially. Their contributions must be measured against a backdrop of surgery and enforced inactivity.

Fitzgerald (neck) has not played since last season’s Heineken Cup semi-final victory over Clermont Auvergne, Kearney (back) was injured in September while O’Driscoll (ankle) last saw action in October.

Leinster are currently sixth in the RaboDirect Pro12 table – they lie three points off second place – so victory tonight is a pressing concern but the two subsequent weekends will define their season. The European champions must pursue a 10-point haul in their final two pool matches against the Scarlets and Exeter Chiefs just to contend for a place in the knockout stages of the tournament.

The significant broadening of the squad’s talent genes is a timely fillip in pursuing that quest, albeit the timeframe for integration is minuscule. Ireland coach, Kidney is the more latent beneficiary as the aforementioned players hone their match sharpness over the next three weeks or so ahead of Ireland’s opening match in the Six Nations Championship next month.

Sole survivor

Schmidt has retained only two players who started against Connacht at the RDS, Fionn Carr moves from the left to right wing to accommodate Fitzgerald’s return while Devin Toner is the sole survivor in the pack. Shane Jennings has recovered from illness and is named among the replacements. Isa Nacewa (arm) and Richardt Strauss (knee) have been given more time to rehabilitate injuries while Fergus McFadden is rested.

Edinburgh endured a torrid end to 2012 losing four consecutive matches in what has been a largely disappointing season, particularly in Europe. Their last victory in the league was a fine 23-13 win at Murrayfield against the champions, the Ospreys.

Former New Zealand Under-21 World Cup winner Ben Atiga plays for the first since October following a knee injury, while Stuart McInally, Georgian international Dimitri Basilaia and David Denton are decent ball carriers in a reshaped backrow. South African Willem Nel replaces Geoff Cross at tighthead prop.

Leinster will look to focus on the process of building a good performance rather than becoming blinded by the outcome. They’ll want to establish a tempo and rhythm to their patterns that they can take forward over the coming weeks.

Build the platform

First though they must build the platform; improve the scrum, guarantee solidity in the lineout, seek out Edinburgh’s weak points, whether that’s on the fringes of the breakdown or further afield. Leo Cullen’s direction, the robust carrying of the backrow – Cian Healy and Seán Cronin too – and the intelligent game management from the halfbacks Eoin Reddan and Jonathan Sexton are key components. They’d want to shut down Tim Visser while they’re at it.

The Scots have proved to be perplexing opponents for the Irish province in the past, something to which a fit again Kevin McLaughlin alluded: “We went through a phase for a number of years where we couldn’t buy a win there.”

It promises to be an instructive night, individually and collectively.

Injury watch Who's back and who's not

LEINSTER

BACK IN ACTION

Brian O'Driscoll (ankle). Last game: Oct 27th.

Rob Kearney (back). Last game: Sep 28th .

Luke Fitzgerald (neck). Last game: Apr 29th .

STILL OUT

Isa Nacewa (arm). Expected back: For final two rounds of Heineken Cup

Eoin OMalley (cruciate), may return to squad next week

Quinn Roux (dislocated shoulder), April at earliest

MUNSTER

BACK IN ACTION

Keith Earls (groin) – Last game: Dec 8th.

CJ Stander (hand) – Last game: Dec 1st.

STILL OUT

Paul O'Connell (back), April at earliest after surgery

Niall Ronan (neck), may return next weekend

ULSTER

BACK IN ACTION

Dan Tuohy (torn calf). Last game: Dec 15th

OUT OF ACTION

Stephen Ferris (ankle), underwent surgery at start of December.

Johann Muller (arm), February

Tommy Bowe (knee), April

CONNACHT

OUT OF ACTION

An extended list that includes: John Muldoon (knee), February; Frank Murphy (cruciate), unknown; Matt Healy (hand), 2-3 weeks.