12 Dec, 14:42
Prop Cian Healy is expected to miss the start of the 2014 RBS 6 Nations after undergoing surgery on his injured ankle on Wednesday.
Ian McGeechan and his coaching staff have gone even younger for the tour's third match against the Cheetahs, pitting 21-year-olds Keith Earls and Luke Fitzgerald together in an all-Irish midfield.
Earls will be keen to play his way back into Test contention after a shaky display against the Royals, during which he picked up some damage to his right shoulder.
Happily recovered, the Munster tyro is back to full fitness and has looked sharp in training this week.
For Fitzgerald, a Grand Slam winner like Earls, Saturday's game will mark his debut in the the tourists' famous red jersey and gaining his first Lions cap alongside Earls will make it all the more special.
"Myself and Earlsy, we know each other very well. I think the first time that we played together was when I was on an Irish Schools team when I was at full-back and he was at 12," said the young Dubliner.
"We also played against Canada last November, when he scored a try with his first touch in international rugby.
"But we've definitely never actually played in the centre together, so it's pretty exciting.
"It's great to play with someone that you've effectively grown up with, and especially in a game of such importance."
Fitzgerald's father, the former Ireland prop Des, is sure to be bursting with pride as his son runs out at Vodacom Park.
Des actually played for the Lions in a match against a Rest of the World XV in Cardiff back in 1986, which was one of the highlights of the centenary celebrations of the International Rugby Board.
Having picked up a chest infection and a slight knee injury, Luke has had to bide his time as Earls, Jamie Roberts and Brian O'Driscoll shared out the number 13 and number 12 shirts for the Lions' opening wins over the Royals and the Golden Lions.
"There's an awful lot of pressure there after the way the guys performed during the week," he admitted.
"But I think it's important for us to shelve that at this stage. We have to somehow try not to force things too much and be patient with the game.
"To be honest, I'm delighted just to getting out onto the pitch at this stage. It's been tough watching the guys playing and I'm just really looking forward to getting out there."
Many will argue that Fitzgerald's best chance of getting into the Lions Test team will be in a different position - out on the left wing where he has played for Leinster and Ireland with such distinction this season.
He has grown in stature in his first full season of Test rugby, scoring his first senior tries in a man-of-the-match display against Italy and peppering Ireland's Grand Slam run with some brilliant attacking plays and defensive cameos.
More of the same could see him flourish on this South African tour, especially as his versatility will stand to him when McGeechan and company sit down to ponder over their line-ups to face the Springboks.
Following Fitzgerald's career from schoolboy wonderkid through to the Lions, time and again he has shown his enviable ability to slot in at full-back, in midfield and out on the wing.
Wherever he is picked, the Blackrock College clubman almost always makes his mark on a game and that is what has Lions fans licking their lips for the Cheetahs tie.
"Without wanting to confuse things, I actually see myself as a 15! I suppose I really should try to nail down one of the positions that everyone keeps picking me in," he added, with a smile.
"I do love playing in the centre, though, because you do get your hands on the ball more on the wings.
"And really, I'm just glad to be involved. I feel pretty lucky to be here.
"It's unbelievable when I think about it. It's the dream for any kid who grows up playing rugby in any of the four home unions.
"When you play for Ireland you're representing five or six million people; if you play for the Lions you've got something like 70 million people behind you.
"So that's a bit of pressure but it's something that I'll enjoy."
The midfield combination of Fitzgerald and Earls undoubtedly has the potential to be explosive.
If you look back to one of the first weekends of the 2008/09 season, when Fitzgerald scored a hat-trick of tries against Edinburgh and Earls did likewise against the Dragons 48 hours later, you can see why the Lions came calling. Two prized Irish gems.