Milestone man Aliir Aliir loves a bleached-blonde mohawk, has the biggest grin at the Sydney Swans and can often be found pulling swift moves with a basketball.

But defence coach Tadhg Kennelly says there’s a lot more to the star Swan than his cheery air, lauding the “presence” and “competiveness” he asserts in a game.

Aliir will celebrate his 50^th AFL match as Sydney squares off with St Kilda at the SCG on Saturday afternoon, and if Kennelly’s words are of any indication, Aliir will be firmly in the sights of the Saints.

“He has a real presence about him and a competitiveness about him when he plays footy,” Kennelly said.

“He’s got a really jovial, light-hearted and laconic nature, and he brings that energy and happiness. But he also plays with a real competitiveness and a presence, and he’s a big man. The rest of the competition is looking at this bloke going, ‘Where is he? Where is he?’ Every time they kick the ball inside our defensive 50 he’s got that real big-man presence.”

An ability to clamp tall and small forwards, precise ball use and prolific intercept marking have seen Aliir become a crucial cog in Sydney’s back six. 

When the big-framed Swan returned from an extended stint in the NEAFL in Round 13 last season, he racked up 18 touches and six intercept marks in a game that reignited his career.

The 24-year-old hasn’t missed an AFL match since, and he is this year averaging a Swans-high 2.8 intercept marks per game.

But while defence is Aliir’s cornerstone, he’s also played significant roles in the ruck in absence of Sydney’s three primary big men: Sam Naismith, Callum Sinclair and Darcy Cameron.

Kennelly says Aliir’s flexibility is a massive plus for the team.

“He’s been a big asset. We’ve had to use him in the ruck because of our ruck dilemmas, and he’s gone in and done a job for us as a ruckman. He has an ability to swing and get in there and do a job for us, and it shows great versatility for him to be able to do that,” Kennelly said. 

“He’s that imposing centre half-back that’s intercepting. He’s the number one intercepting player at the club and the number one spoiler at the club, and they’re the figures you want if he’s playing down back. But he’s also been able to do some good jobs for us in the ruck.

“Last week against Max Gawn his ability to get after the ball on the ground was terrific and he gets some centre clearances. It was the same thing against Port Adelaide. He’s got an ability to get after the ball and a lot of other ruckmen don’t have that quick feet. He’s cat-like and is up and back on the ball as quick as anyone, so he’s an extra midfielder for us at times.”

Aliir will emerge on the SCG on Saturday to the cheers of his family.

Kennelly knows how special it is to mark a momentous occasion in front of family; his mother Nuala and sister Joanne travelled from Ireland to see him make his AFL debut at the SCG in 2001.

And like Kennelly, Aliir’s love for his family runs deep.

“It’ll be huge for him to play in front of his family,” Kennelly said.

“If you get to know what motivates Aliir it’s always his family.”