Adelaide coach Matthew Nicks suspects rule changes designed to speed up the AFL have led to a spate of hamstring injuries at the Crows.

Adelaide have lost in-form defender Wayne Milera to a hamstring strain for Saturday night's grudge match against Port Adelaide.

Milera is the eighth Crow to suffer a hamstring injury this season, with the hit list including Izak Rankine, prized recruit Callum Ah Chee and veteran Taylor Walker.

"Across the league, it's a trend I think a lot of teams are working through," Nicks told reporters on Friday.

"With the changes in the game, the speed of the game, it has gone up a lot more high speed than what we're seeing the last few years.

"Extra rotation on the bench; last touch out of bounds - there's a few slight tweaks.

"And a lot of teams are finding some challenges in that space from a games missed point of view."

All Australian contender Milera reported soreness at midweek training, with Nicks describing his injury as minor.

"It was just common sense: no risk taken," Nicks said.

Milera has been replaced by Isaac Cumming, who is making his return from a hamstring injury, while key backman Nick Murray has been dropped in favour of Josh Worrell.

Worrell missed Adelaide's win over Melbourne last weekend due to illness, with Nicks dismissing as inaccurate suggestions the intercept defender had been sidelined for discipline reasons.

The Crows (nine wins, five losses) hold fifth spot and enter the Showdown against the struggling Power as firm favourites.

Port (four wins, 10 losses) languish in 15th and again have been hit by injuries with Esava Ratugolea (patella tendon) and Ewan Mackinlay (knee) out for the season after being hurt last weekend.

Power coach Josh Carr also dropped Todd Marshall, Harrison Ramm and Tom Cochrane, while recalling Brownlow medallist Ollie Wines, Dante Visentini, Jacob Wehr, Brandon Zerk-Thatcher and Mitch Zadow.

"They have had their challenges," Nicks said of Port.

"But they're playing a great brand of footy and I know Josh really well, I have coached with him along my journey and he's a fantastic coach.

"We understand form means nothing when you come into a Showdown.

"They're tight battles more often than not."