ADELAIDE'S hamstring crisis has struck again, defender Wayne Milera ruled out of Saturday's Showdown with Port Adelaide with a hamstring injury.

Milera will miss 1-2 weeks after failing to finish last Saturday night's win against Carlton at Adelaide Oval.

The Crows initially said Milera's injury was to a tendon under his knee, but confirmed on Tuesday afternoon it was to his hamstring.

The half-back flanker is the eighth Crows player – joining skipper Taylor Walker, Matt Crouch, Eddie Betts, Kyle Hartigan, Sam Gibson, Kyle Cheney and Lachlan Murphy - to have a hamstring injury this season.

"The scans haven't revealed anything too significant, more some distal tendon irritation behind his knee," Crows general manager of high performance Matt Hass told afc.com.au.

"He won't play this week against Port Adelaide, but he'll be assessed for the following weekend."

Walker and vice-captain Rory Sloane (foot) will have to complete Wednesday's main training session to prove their fitness for the Showdown.

"Taylor had a great session on Saturday and trained in a high-intensity session yesterday," Hass said.

"He'll train with the group on Wednesday and should he pull up well, he'll be available for Port Adelaide.

Of Sloane, Hass said, "We decided to back him off (after round four) and make sure that foot was fully settled, and he's done a mountain of work since.

"He did a massive session on Saturday with the rehab crew.

"Again, he'll train this Wednesday and should he get through that be available for the weekend."

Forward Riley Knight is also under a cloud after he had his workloads managed and was rested from the win over the Blues.

Key defender Hartigan will miss a third straight game but could be a chance for the round nine clash with the Western Bulldogs.

The Crows now have a massive 14 players, or almost a third of their list, either facing fitness tests or unavailable this weekend.