NEITHER Patrick Ryder nor Jackson Trengove will line up for Port Adelaide on Friday night against Geelong at Adelaide Oval.

Trengove injured his ankle in round eight against Richmond and will likely return next week against Carlton, while Ryder won't play until after Port's round 13 bye due to an Achilles injury.

Coach Ken Hinkley was confident the continued absence of the ruckman and defender wouldn't affect his side's performance against the Cats.

"'Jacko' (Trengove) was really close, he probably could have nearly played this week but with the injury that he's had we wanted to err on the side of caution," Hinkley said on Thursday morning.

"Paddy's the same; Paddy trained on Tuesday, there's no doubt we could have put Paddy on the park tomorrow night but the long-term effect of that might have been that we lose him for a bit longer.

"We won't play him until after the bye.

"We've won the last couple of weeks without either of the boys and we'd love to have them in the side, don't get me wrong … but that's a footy season – you're going to have blokes missing and you don't dwell on who's not there."

Trengove's three-week injury break is just the latest in a frustrating number of interruptions he's endured in Hinkley's time at the club.

A shoulder injury ruined the end of his pre-season, a knee injury did the same to the tail end of his 2014 pre-season and another ankle injury ruled him out for a month late last year.

He's an aggressive defender and Hinkley said the injury toll was simply a cost he had to pay – he didn't want Trengove to ease off even a bit.

"He's a big, big person, he's 197cm, he's a gangly big bugger and he's a competitor," he said.

"If you look at his injuries, they've been combat injuries – he's done his ankle, he hurt his knee, he's hurt his shoulder – all those sorts of things.

"I hope that he stops getting the injuries but I definitely don't want him to stop the combativeness of the way that he plays."

Hinkley also said that Karl Amon would have to prove his fitness at training on Thursday after the young midfielder complained of a sore calf.

With both the Power and the Cats locked at 5-5 entering round 11, the coach wasn't afraid to speak of Friday night's importance.

He said it was vital – for both confidence and premiership points – to head into the second half of 2015 with more wins than losses.

"After round 11 it's halfway, if you turn 6-5 and you can at least do that in the second half of the year it nearly says you're going to play finals," he said.

"That's the challenge – but you don't want to be starting the second half of the year in the negative.

"Geelong won't want to do that and we certainly don't want to do that so it's a pretty significant game."