IN-FORM St Kilda captain Jarryn Geary has defended out-of-favour key forward Paddy McCartin's work ethic as the scrutiny continues on the prized pick of the 2014 draft class.

McCartin, who turns 21 this month, lost his spot in the Saints' senior side after a goalless, five-disposal day against the Brisbane Lions in round three.

He has not kicked more than two goals in any of his 19 matches to date and his athletic limitations, on top of being a type-one diabetic, have drawn attention.

Josh Bruce and Tim Membrey managed two goals apiece in McCartin's absence on Sunday, as St Kilda beat Collingwood by 14 points for its second win of the year.

"There's always going to be (scrutiny) with a No.1 draft pick, but it's tough for young key forwards to perform straightaway consistently," Geary told 3AW.

"He's probably not a natural athlete, in terms of some other key forwards in the competition – he's a big brute of a lad – so that's the way he plays his footy.

"It's hard to compare him against other key forwards, like 'Rooey' (Nick Riewoldt). You see 'Rooey' run around and explode off his opponent, (but) Paddy's not that type of player.

"He's more of a stay-at-home forward who's going to eventually be able to out-muscle defenders … I'm confident with time he'll be really good for us."

Coach Alan Richardson also fielded a question in his post-match press conference about McCartin's training efforts in comparison to six-time club champion Riewoldt.

"I am pretty sure the footy world knows how professional (Riewoldt) is. He's an amazing athlete with the way he prepares himself," Richardson told reporters.

"He's a great example for a lot of our young players, including Paddy, to see the way he goes about his preparation and footy to give himself every opportunity to perform consistently."

The Saints' No.1 ruckman Tom Hickey struggled against Pies big man Brodie Grundy on Sunday, particularly in the opening half, and could find himself under pressure from understudy Billy Longer.

Hickey and Longer joined St Kilda from the Gold Coast and Brisbane Lions in 2012 and 2013 respectively, and both stand above 200cm.

"Billy's been performing really strongly over the JLT series and in the VFL practice matches and again over the weekend," Geary said.

"That's all he can keep doing – putting pressure on Tom – and if he gets his opportunity, he'll obviously take it.

"But Tom's played some really valuable games for us … we're pretty confident with both of them when they're in the team, that they're going to be able to perform really strongly."

Geary was also complimentary about the performances of defenders Dylan Roberton and Jimmy Webster and midfielder Seb Ross, who quelled Collingwood star Adam