St Kilda vice-captain Lenny Hayes expects tall forward Justin Koschitzke to thrive under the added responsibility when he returns to play Port Adelaide in Saturday night's AFL game at AAMI Stadium.

Koschitzke has served a three-game suspension and will give the Saints a focal point in attack while Nick Riewoldt is sidelined by his hamstring injury.

Hayes said Koschitzke had a good record of stepping up whenever Riewoldt was sidelined.

"We're obviously crying out for a tall target down there and tried a few different things there last week," he said on Wednesday.

"Kosi's a great player for us and every time he's been there and Rooey's been out with injury he's really taken that role on and played really well for us.

"So I think he's pretty excited to get out there this weekend."

St Kilda are unbeaten after four rounds even though Koschitzke and Riewoldt have missed games, and Hayes said the results were evidence the Saints had good depth and were playing well as a team.

He said he would not take much notice of Port's heavy loss to Geelong last Sunday, and expected a tough fight with the Power.

"They're a very proud club and we've always had really good battles against them," he said.

"Until last year they'd had a very good record against us and we always know we're in for a really good contest."

Meanwhile, St Kilda star Lenny Hayes disagrees with his coach's call to shorten AFL games because he likes how the Saints wear opposition down.

After Sunday night's hard-fought win over Fremantle, Lyon floated the idea of games being cut to two 45-minute halves because four 30-minute quarters was too long a stretch for players, coaches and fans.

Lyon's suggestion came amid ongoing discussion on whether the length and speed of the game is having too great a physical toll on players.

Contrary to Lyon's view, Hayes said capping the number of times teams could use the interchange bench would slow the game and limit serious hamstring injuries, such as the one Riewoldt suffered in round three.

Hayes said he enjoyed how effective the Saints were at going the distance, like they did against the Dockers.

"I probably prefer the game to go longer," he said.

"I like the way we seem to wear teams down in the last quarter, it's a real battle of attrition.

"To be honest I don't mind it (the game's duration) the way it is.

"I don't like seeing the good players doing those hamstrings and things like that so maybe something with the rotations, I think there's a bit in that."

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