But Geelong have an equally-athletic Irishman in Oisin Mullin ready to shut one of them down.
It's just a matter of who.
Whatever lever Cats coach Chris Scott chooses to pull, Blues counterpart Josh Fraser believes his midfield can handle the heat at the MCG on Friday night.
"Walsh, Smith, (Patrick) Cripps - we've got a few guys playing reasonable football," Fraser said.
"We're clearly not privy to their thinking, but our guys will all be well-prepared if that happens.
"He's (Mullin) been such an influential player for them over the course of the season, being able to nullify teams' midfielders.
"Our boys - all of them - will be prepared for him in some capacity."
Mullin, 26, has been integral to Geelong, shutting down a star and burning them the other way with his running.
He could be the next task facing classy 20-year-old Smith, who kicked two clutch last-quarter goals to go with 29 disposals in last week's wildcard win over Melbourne.
Rising Star winner Smith has shone in his debut season - after missing last year with an ACL tear - and Scott will consider tagging him ahead of Cripps and Walsh.
"That's high praise if you're going to prioritise him in front of those two," Scott said.
"But yeah, it's definitely a consideration. He's going really well.
"I know he's a very young player early in his career, but there's some people that I really rate that thought his knee injury last year was really going to cost them and I was like 'you might be overrating him a tad'.
"But they've been proven likely correct, given the way he's gone.
"Even early in the season, it's hard to come back from a knee and be at your best, but he seems to be finding that by this stage of the season.
"He balances them out really nicely. They've got some really highly credentialed mids. (Adam) Cerra's an example who is not playing in there as much anymore, I suspect because Smith's in there.
"We'll be thinking about him a lot."
Fraser has consistently praised Smith's ability to level up his game and doesn't expect a tag to faze him.
"He'll be fine. It'll be another learning opportunity for him," he said.
"He's a kid that has embraced everything that has been thrown at him. Highly competitive, he'll have great support around him from his teammates.
"There aren't too many scenarios where I'm concerned about how Jagga will handle it. That doesn't guarantee anything of course, but I don't think it'll rattle him too much."
Geelong's other Irishman, defender Mark O'Connor, is another option to blunt the Blues' weapons.
"They've got a lot of great players," the 29-year-old said.
"So we'll just try and put something in place and see how we go."
Carlton could turn to youngster Cooper Lord, who ran with Melbourne star Kysaiah Pickett last week, to curtail hard-running Cats gun Bailey Smith.
"We've given him a couple of big assignments over the last fortnight and he's handled them really well," Fraser said.
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