O'Brien will miss this weekend's clash against Melbourne and is in doubt to return for Adelaide's last game of the season the following week against North Melbourne.

The Crows' reigning club champion suffered a low-grade ligament tear in his right knee in Adelaide's four-point loss to Port Adelaide last Saturday night.

"The most appropriate course of management for Reilly is to miss this weekend's game against Melbourne," Adelaide's head of football Adam Kelly told the club's website.

"He will not require surgery and is expected to recover fully but that may not be in time for the round 23 clash with North Melbourne."

The Crows will also be without defenders Brodie Smith and Will Hamill for their clash against the ladder-leading Demons - both were concussed against Port.

And experienced duo Matt Crouch (groin) and Daniel Talia (foot) have been ruled out for the remainder of the season.

Both Crouch and Talia did not play a premiership game this season because of their respective injuries.

Both Crouch, 26, and Talia, 29, fall off-contract at season's end.

Australian Associated Press