ADELAIDE is anticipating scans on the left knee of defender Matthew Jaensch to confirm he has ruptured his ACL.

The severity of Jaensch's knee injury will be revealed by Sunday evening, but even the Crows admit it doesn't look good. His knee gave way as he tried to change direction in the third quarter against St Kilda on Saturday at Adelaide Oval, as he enjoyed the continuation of what had been a stellar start to 2015.

The club's defensive depth is being truly tested, but coach Phil Walsh insisted its versatility would see it manage the latest trial.

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"I actually thought a move today worked really well for us, we put (Rory) Laird onto (Jack) Steven – (David) Mackay was set for that job – and Mackay went back," Walsh said. "We got benefit out of both the moves.

"We may look at using Mackay there a little bit more.

"I don't want to lose Matthew Jaensch but this is the caper we're in – someone steps up.

"They have a saying in the NFL: 'Next man up' and that's what we've got to do."

Jaensch's is the latest name added to a significant injury list that includes Rory Sloane (cheekbone), Richard Douglas (foot), Brad Crouch (broken foot), Brodie Smith (concussion) and Josh Jenkins (hip). Jenkins is expected back next week while Smith will be assessed after being concussed for the second time in a month against the Saints.

Cam Ellis-Yolmen is also tipped to return next week against Greater Western Sydney, which will mark the start of a three-week period that Walsh said could set the Crows up for a finals tilt. Another three wins would have them sitting at 8-2 and entrenched inside the top four.

"These next three games are really important games for us to set our season up.

"Really good opposition, GWS in Sydney then Fremantle at home and Carlton have got some players back.

"These next three games will give us an opportunity to get into position."