Ireland lost 11 players to the British and Irish Lions, who are currently on tour in Australia. Those 11 have a combined 528 caps and 834 points.
Saturday's Ireland starting 15 has a combined cap count of 191, in contrast. The Canadian starters have 292 combined caps.
But all of the touring Irish play professionally back home for Munster, Leinster and Ulster.
"A massive challenge," Canadian coach Kieran Crowley said of the Irish.
Only seven of Canada's starting 15 play professionally. The rest may be full-time rugby players, training and eating likes pros at their training base in Langford, B.C., but they lack the week-in, week-out top-echelon competition.
So a visit by Ireland, ranked eighth in the world by the International Rugby Board, is something special no matter the visitors' lineup.
"This is the big scalp," said Canadian captain Aaron Carpenter, who will play for the Cornish Pirates in England's second tier next season.
"We've been building towards this one," said Crowley, a former All Black.
More than 18,000 are expected to take in Saturday's match at BMO Field.
The 13th-ranked Canadians have never beaten Ireland, which holds a 4-0-1 edge in the series. Canada tied Ireland 27-27 in Markham, Ont., in 2000. Ireland won 25-6 in Vancouver in 2009, the last time they met.
"We expect them to be a well-drilled team," said acting Irish coach Les Kiss, noting the Canadians have spent plenty of time together in recent weeks.
"In the footage that we've watched lately, they seem to be in a good place."
The touring Irish, in contrast, will have had 11 training sessions in three weeks.
"That's not a lot of time to put a lot of things together, particularly with a lot of younger players," said the Australian coach.
Carpenter, like many in the Canadian camp, abhors the amateur label.
"Because we train like professionals," he said.
Said Crowley: "I've worked with a lot of pro players in New Zealand and these players here in Canada are some of the best professional players I've ever worked with. It's just that they don't get paid.
"If you ask some of the professional players in other countries to do some of the things that these boys do as amateurs, the professional players would tell you to stick it probably."
"There's no drop-off between the (Canadian) pros and the amateurs," added Jebb Sinclair, who plays for England's London Irish. "These guys are freak-show athletes.
"What they need now is experience: 20, 30, 40 games a year at a professional level."
But Canada is at a disadvantage in Europe because of the so-called Kolpak ruling, which allows clubs to sign players from South Africa and the Pacific islands without limit.
Canadians, in contrast, fall subject to rules on import players.
As for the pro versus amateur debate, Kiss says amateurs can be "a dangerous animal."
"There's another reason they play that's outside the professional realm and there's another heart and desire that comes to their game. I don't see any less desire and passion and intent in their game when they out on the Canadian jersey."
You might never meet a prouder national squad than the Canadian rugby team.
Canadian flags galore adorn their dressing room area and, arm-in-arm, they belt out "O Canada" before games with unabashed pride. The solidarity of the squad is shown when they come off the field in a phalanx formation, holding on to the next man's shoulder, after the pre-game warmup.
Despite the odds, Canada could be catching Ireland at the right time. In addition to the depleted lineup, the Irish had to contend with a bug that swept through the squad during midweek.
Kiss points to Canada's tactical advances in recent years and agrees that success in the sevens side of the game has benefited the 15-man version of the game here.
"We'll have our work cut out on Saturday," acknowledged No. 8 Peter O'Mahony, who took over as Irish captain after hooker Rory Best was summoned by the Lions in the wake of Dylan Hartley's suspension.
The Irish, however, are just as motivated as the Canadians.
"Any time you pull on an Irish jersey, it's a big occasion," said O'Mahony. "It's a huge honour and every time you step into a test arena you're being monitored by someone."
"It's the stage that you want to be playing on and testing yourself at," he added. "It's not just showing off to the coaches. You want to prove to yourself as well that you're able to play in the test arena and that's guys are going to be looking to do Saturday."
It could be a day of milestones. Australian-born kicker James Pritchard, who will be making his 49th appearance for Canada, needs just seven points to overhaul former captain Gareth Rees' national record of 491 points.
Pritchard is a world-class kicker who is extremely accurate from 40 metres in. He was good on all seven attempts last week against Tonga.
Centre Ciaran Hearn looks after the long-range Canadian attempts.
Winger Andrew Trimble will win his 50th cap for Ireland. Centre James Downey earns his first cap, at the age of 32.
Five players made their debut last weekend when the Irish edged the 17th-ranked U.S. 15-12 in Houston.
"This is invaluable for Irish rugby, to get this many players out as a young squad," said O'Mahony, who will earn his 16th cap Saturday.
While the Irish play at a high club level, O'Mahony argues that you can't replicate test rugby.
Canada has geared up for the game with wins over No. 12 Tonga, No. 14 Fiji and the Americans.
Those games left a mark or two. Winger Matt Evans was a late scratch from the lineup to face the Irish after failing to overcome a concussion from a late Tongan hit. Sean Duke also was kept out of the lineup due to a concussion.
But forward Jebb Sinclair, floored by a Tongan punch to the face, was cleared of his concussion issue and will play albeit it with a bloodshot eye and mouse underneath.
The punch earned Tongan prop Edmund Aholelei a three-week suspension.
Crowley played three different men at fly half the last three games, with Nathan Hirayama winning the battle to start against the Irish.
Sinclair moves into the second row, allowing Tyler Ardron a spot in the back row.
Pritchard shifts from fullback to fill Evans' position on the wing while Connor Braid comes in at fullback. Liam Underwood and Pat Parfrey are added on the bench.
A knee injury keeps back Nick Blevins out of the matchday 23.
The Canadians leave Sunday for Japan and their Pacific Nations Cup finale on Wednesday in Nagoya.
Connor Braid, James Pritchard, Matt Evans, Ciaran Hearn, Harry Jones, Taylor Paris, Nathan Hirayama, Phil Mack; Aaron Carpenter (capt.), John Moonlight, Tyler Ardron, Tyler Hotson, Jebb Sinclair, Jason Marshall, Ray Barkwill, Hubert Buydens. Reserves: Ryan Hamilton, Andrew Tiedemann, Doug Woolridge, Jon Phelan, Nanyak Dala, Sean White, Liam Underwood, Pat Parfrey.
Felix Jones, Fergus McFadden, Darren Cave, James Downey, Andrew Trimble, Ian Madigan, Isaac Boss; Peter O'Mahony (capt.), Tommy O'Donnell, Kevin McLaughlin, Devin Toner, Dan Tuohy, Mike Ross, Richardt Strauss, Tom Court. Reserves: Sean Cronin, David Kilcoyne, Declan Fitzpatrick, Mike McCarthy, Chris Henry, Paul Marshall, Paddy Jackson, Robbie Henshaw.