The first of the NatWest 6 Nations squads was revealed this week with Conor O'Shea announcing his extended Italy selection.
Those included will be keen to stake a claim for the final 31-man squad, while with more squads set to be announced next week, everyone will be anticipating the return of European action.
With just two rounds remaining in the Champions and Challenge Cup pool stages, it is all to play for in the quarter-final races.
FRANCE
Jacques Brunel met with the Top 14 coaching staffs this week as he continues to settle into his new role in charge of Les Bleus.
And he will have been pleased see the return from injury of Rémi Lamerat, who has been out of action since the start of December.
His Clermont and France teammates Wesley Fofana and Damian Penaud are both out of at least the start of the Championship, so the fitness of Lamerat, who started all five games last year, will be good news for Brunel.
There was also confirmation this week that former France full-back Nicolas Jeanjean will be joining the coaching set-up as a fitness trainer for Les Bleus.
Elsewhere Virimi Vakatawa remains in the centres for Racing 92 against Munster, while Anthony Belleau gets the nod at fly-half for Toulon against Benetton and Yacouba Camara continues his return to full fitness with Montpellier
WALES
In the week that Dan Lydiate was ruled out of the Championship, Warren Gatland will be pleased to see Ross Moriarty fit enough to make his return to action with Gloucester in Agen.
The flanker has not played since featuring in the Anglo-Welsh Cup in November, his only appearance this season to date.
However, he will have the chance to stake a claim for a spot in the Welsh back row, which is already without Sam Warburton, while Taulupe Faletau is also in a fitness battle to be ready for the start of the campaign.
There is more good news with Liam Williams fit again and back for Saracens in their crucial trip to south Wales.
The former Scarlet will take on old rivals the Ospreys in a crucial match in the race for a quarter-final spot.
Victory for the Ospreys would give them a real shot of making the last eight, while only two wins from two this fortnight for Saracens will keep their hopes of a third straight European title alive.
IRELAND
The big news for Ireland is the absence of Sean O'Brien with a hip problem which will keep him out of not only Leinster's European pool clashes, but also the start of the Championship.
As a result, there is a spot up for grabs in the Ireland back row, with Leinster's back row of Jordi Murphy, Josh van der Flier and Jack Conan all looking to stake a claim, as will replacement Dan Leavy.
Just as interesting is the decision to go with Jordan Larmour at full-back, the 20-year-old set for his first European start after some fine recent displays domestically.
They face Glasgow Warriors knowing that a win, along with a defeat for Montpellier at Exeter Chiefs, who wrap up top spot and a likely home quarter-final.
Munster are also well-placed ahead of their trip to Paris to take on Racing 92, and can call on a pair of international back-rowers of their own in Peter O'Mahony and CJ Stander.
Finally Garry Ringrose's injury means there will be lots of competition in the centre, with Stuart McCloskey - playing for Ulster against La Rochelle - and Bundee Aki - starting for Connacht at Worcester - having both featured in November.
SCOTLAND
Stuart Hogg's return to action will have to wait another week as Ruaridh Jackson continues in the No.15 jersey for Glasgow Warriors as they travel to Dublin to take on Leinster.
With Finn Russell also absent, it will instead be Peter Horne who starts at fly-half alongside Scotland international Ali Price.
For Edinburgh, the return of Rory Sutherland at loosehead will be crucial as they look to book their place in the last eight with a win at home to Stade Français.
Following injuries to Darryl Marfo, Allan Dell and several others in the front row, Sutherland will be keen to show his worth against former Wallaby tighthead prop Paul Alo Emile ahead of the squad announcement on Tuesday.
ENGLAND
Joe Launchbury missed Wasps' defeat to Saracens last week but he is back in the starting lineup for the crucial clash with Harlequins at the Stoop.
Dai Young's side know that only a win will keep them in contention for the quarter-finals ahead of next week's home clash with Ulster.
Before that on Friday night, Bath welcome back Sam Underhill, with the flanker looking to prove his fitness having not played since turning out for England during the Autumn Internationals.
ITALY
Alessandro Zanni returned to the Italy squad this week, and will be targeting a 100th cap for the Azzurri in the 2018 NatWest 6 Nations.
He is named on the bench for Benetton as they travel to France to take on Toulon, while all-international half-back duo Edoardo Gori and Ian McKinley pulls the strings in the backs.
Uncapped flanker Jake Polledri was another eye-catching inclusion by O'Shea, and he will start in the back row for Gloucester, who travel to Agen looking to stay in contention for top spot in their Challenge Cup group.
HEAD TO HEADS
REC BATTLE
There are a couple of particularly interesting match-ups when Bath host the Scarlets in one of the most important games of the weekend.
With Ellis Genge injured and Joe Marler suspended, Beno Obano has the chance to build on his call-up to the England squad in November, and on Friday night goes up against Wales tighthead Samson Lee.
Their scrum battle could be crucial, while in the backs, Hadleigh Parkes, capped for the first time in November, lines up opposite Jonathan Joseph in the centres.
FRANCO-IRISH INTRIGUE
Ulster host La Rochelle and Munster travel to Racing in two games which will have big implications on the quarter-final make-up.
Two players who made their Test debuts in 2017 will go head-to-head in Belfast as Jacob Stockdale lines up opposite Gabriel Lacroix.
The former has four tries in as many Test starts, while Lacroix also crossed on debut against Japan, while adding two more in the non-cap encounter with New Zealand.
That is not the only interesting pre-cursor to the Championship opener in Paris, with Racing hosting Munster.
Virimi Vakatawa starts at outside centre, opposite new Ireland cap Chris Farrell, while on the wing Teddy Thomas and Keith Earls will both be looking to get the edge on their opposite numbers.
LIONS IN SWANSEA
There will be a reunion of British & Irish Lions at the Liberty Stadium when the Ospreys host Saracens with both teams desperately in need of a win.
Dan Biggar and Owen Farrell will be crucial to their team's chances at ten, but just as interesting is the match-up between Lions second row partners Alun Wyn Jones and Maro Itoje.
The latter is just back from injury, and will face a stiff challenge with Jones having played an important role in the Ospreys' derby win over Cardiff Blues last time out.
OTHER MATCH-UPS
There are a number of other head to heads to watch out for, particularly in the forwards.
When Exeter Chiefs host Montpellier, Sam Simmonds will have to cope with the carrying power of Louis Picamoles, while Courtney Lawes is shifted to the back row for Northampton Saints as they play host to Clermont.
Finally, Leinster's Robbie Henshaw will be the latest person charged with slowing down Huw Jones, who makes his fourth start for the Warriors and enjoyed a fine first half of the season.