The 29-year-old - son of Blackrock-born former hockey international Katherine Doyle and brother to Ireland reserve scrum-half Guy - has made the blindside berth his own since a four-game salvo at the 2003 World Cup.
Set for his 42nd cap at the Millennium Stadium, Easterby knows - apart from bragging rights with his Llanelli colleagues - there is so much else riding on Saturday's result.
"Wales might be in the driving seat but it's still all to play for. We want to set the record straight and prove that a good team does not become a bad one overnight," admitted the Scarlets skipper.
"After winning the Triple Crown last year we set our standards a bit higher this season. When you set that type of standard it's bitterly disappointing to end up without the prize we had hoped to win.
Sure, the Grand Slam is no longer on the agenda but we still have a lot to aim for. More importantly there is a lot to prove."
Having penned a new three-year deal with Llanelli earlier this month, despite the club's failure to reach the Heineken Cup quarter finals for only the second time in seven seasons, Easterby is a defensive giant among the Irish squad.
Going through large tracts of unseen work, the current campaign may not have seen him hit the heights of 2004 yet, but the bounty of a Lions call-up could still be in the offing come June.
One player who should figure amongst Sir Clive Woodward's thoughts, and who will tango with Easterby in the trenches tomorrow is inspirational Wales back row Martyn Williams.
"Martyn is benefiting from the way Wales play. He's a great footballer and likes to get the ball in hand. I have a lot of respect for him and he deserves all the credit he's been getting this year," claimed Easterby.
"He has been Wales' outstanding player."
Outstanding or otherwise, Ireland's final flourish in this year's Championship needs a big performance from Easterby as the forward tussle is tantamount to a much-needed fourth win.
"Going to Cardiff is our chance to put the French defeat to bed and put things right. We can still win four out of five and that would be something at least from a season in which we felt good enough to win the Grand Slam."
Simon Henry Easterby Date of Birth: 21/07/1975; Place of Birth: Harrogate, England Height: 6ft 3in
Scoring Record: 2000: 2 tries v United States; 2002: 1 try v Scotland, 1 try v Georgia
FOR THE RECORD:
Easterby was one of five players - including halfback duo Ronan O'Gara and Peter Stringer - the current Ireland squad to make their debuts against Scotland in the 2000 Six Nations. John Hayes and try scorer Shane Horgan were also making their international bows.
The 20-point victory - a first over the Scots since 1988 - marked a new era in Irish rugby with coach Warren Gatland at the helm.
Six Nations: February 2000: Ireland 44 Scotland 22, Lansdowne Road Scorers: Ireland: Tries: Shane Horgan, Malcolm O'Kelly, Brian O'Driscoll, David Humphreys, Keith Wood; Cons: Ronan O'Gara 2, Humphreys 3; Pens: O'Gara 2, Humphreys Scotland: Tries: Kenny Logan, Glenn Metcalfe, George Graham; Cons: Kenny Logan 2; Pen: Logan
IRELAND: G Dempsey (Terenure College); S Horgan (Lansdowne), B O'Driscoll (Blackrock College), M Mullins (Young Munster), D Hickie (St Mary's College); R O'Gara (Cork Constitution), P Stringer (Shannon); P Clohessy (Young Munster), K Wood (Garryowen) (Capt), J Hayes (Shannon), M Galwey (Shannon), M O'Kelly (St Mary's College), S Easterby (Llanelli), K Dawson (London Irish), A Foley (Shannon). Replacements: F Sheahan (Cork Constitution), J Fitzpatrick (Dungannon), J Davidson (Castres), T Brennan (St Mary's College), G Easterby (Ebbw Vale), D Humphreys (Dungannon), R Henderson (Wasps).
HT: Ireland 13 Scotland 10; Referee: Joel Dume (France)