FRINGE Adelaide midfielder Aidan Riley has had surgery on a broken leg and will miss the rest of the season.

The 21-year-old was playing his second game this season when hurt in a tackling attempt against West Coast on Saturday night.

"It's really disappointing for Aidan," Crows coach Brenton Sanderson said.

"He waited a while for his opportunity and played well after coming into the team last week."

Riley joins key forward Taylor Walker (knee) and backman Brent Reilly (shoulder) on Adelaide's season-ended list.

TheCrows are almost certain to be without key forward Shaun McKernan for at leasta few weeks after he was reported for a head-high hit on West Coast's BradSheppard. 

Hisabsence could see former Richmond ruckman Angus Graham given his first shot inCrows colours, and defender Brodie Smith backed his SANFL form with Sturt. 

Adelaidefaces Collingwood on Friday night at the MCG, a daunting proposition given theMagpies' form last Friday night against Carlton. 

Smithsaid there was no question Collingwood was going to rebound from its shock lossto Port Adelaide the week before. 

Itwas now time for his side to do the same. 

"[It] was avery impressive performance, they're a proud club and they're always going tobounce back from that performance the week before," Smith said. 

"They lookedvery good on Friday night and outworked their opponents so we get to go thereFriday night and bounce back from our performance.

"MCG's thehome of football so you'd like to have a good record there. We've lost our lastcouple there …[we] really need to get a win on the board. 

"We'll befired up."