HAWTHORN has left Melbourne for its clash with Port Adelaide at AAMI Stadium on Friday night without young star Cyril Rioli.

Rioli suffered minor bleeding in his hamstring during the Hawks' loss to Geelong on Easter Tuesday.

Hawthorn coach Alastair Clarkson said the club had decided to take a cautious approach with the 21 year-old given his history of hamstring problems.

"Junior won't play this week," Clarkson said at Melbourne airport on Thursday morning.

"His hamstring injury hasn't been as severe as the last two that he's had, and he could nearly play this week, but given the severity of his last two hamstring injuries he's not totally comfortable with it and we don't want to take the risk with him.

"I'm nearly certain that he'll be available to play for the St Kilda game next week, but there's only been 10 days since the Geelong game so we just didn't want to push it."

Clarkson said Rioli's absence, plus the loss of veteran Cam Bruce to a PCL injury, provided a great opportunity to blood some fresh talent.

Isaac Smith and Paul Puopolo, both taken in the NAB AFL Draft in 2010, will both make their debuts against the Power.

"They deserve their chance and they'll give us a real energy boost too," Clarkson said.

"They're great young lads and they've worked really hard over the summer, so we're really excited about their debut for the club."

Port Adelaide has endured a horror start to the season, winning just one of its opening six games.

But Clarkson said the recent history of tight tussles between the sides meant the Hawks were expecting a tough contest from the Power, regardless of recent form.

"For the last four or five years I don't think there's been more than three or four goals separating either side at the end of the game, whether we've been in front or Port Adelaide's been in front," Clarkson said.

"We've had some great contests over that period of time, and I wouldn't expect anything different tomorrow night."

Port assistant coach Dean Laidley said on Melbourne radio station SEN on the weekend that senior coach Matthew Primus was dealing with a culture problem among his playing group.

Clarkson said his side wouldn't be worrying about the issues or mindset of its opposition.

"We don't want to get caught in this merry-go-round about Port Adelaide being in scratchy form over the last couple of weeks, because we know that's a recipe for disaster for us," he said.

"All we've got to control is the way that we approach the game."

A key strong focus would be on his players' defensive work rate, Clarkson said, voicing his displeasure at conceding 17 goals to the Cats.

"That suggested to me that our willingness to work for one another and tackle and put pressure on the opposition wasn't at the level that we need it to be if we're going to be a really good side," the 2008 premiership coach said.

"So that's what we've got to focus on, and let all the other stuff take care of itself."