Jarrod Croker suffered a season-ending knee injury in round 18.

Raiders winger Jordan Rapana said the side will try and finish what injured skipper Jarrod Croker help start as they try to mount an unlikely finals charge in next six weeks.

Croker was ruled out for the rest of the season after scans showed he would have to undergo surgery after he dislocated his patella twice in his side's victory over North Queensland last weekend.

The Raiders skipper crumpled to the ground early in the first half before taping up his knee and bravely playing on for another 15 minutes before his kneecap dislocated again.

Having played at least 21 games every year since his debut in 2009, Croker's absence leaves a massive hole in a side that is only one loss away from being eliminated from the finals race.

"It's obviously disappointing to lose him, he's a big part of our team and our captain but I think in a way the boys will lift for him," Rapana said.

Raiders winger Jordan Rapana.
Raiders winger Jordan Rapana. ©Nathan Hopkins/NRL Photos

"We all just wish him the best for his recovery and the sooner he's back the better."

Canberra coach Ricky Stuart has recalled Brad Abbey (concussion) for this Friday's clash with the Sharks, which sees Nick Cotric shift back onto the wing while last week's hat-trick hero Michael Oldfield move into the left centre position.

Oldfield celebrated his form against the Cowboys by announcing he had re-signed with the club until the end of 2020.

Having played for six clubs in seven years, Oldfield said it was nice to have a consistent home for the immediate future.

"I've had a great time here so far and obviously I've been given an opportunity and I've been rewarded for it, but I'm really excited to be here for another couple of years," Oldfield said.

Raiders speedster Michael Oldfield.
Raiders speedster Michael Oldfield.

Oldfield has been a fixture in the centres while playing for Mounties in the Intrust Super Cup this season so his shift to cover Croker would not be an issue according to the 27-year-old.

Having earned a spot in the starting 13 seemingly for the rest of the season, opposition teams know they'll have to now allow Oldfield pace after showcasing his sizzling speed against the Cowboys.

He was clocked at 36.1 km/h as he streaked downfield to seal his hat-trick and the game for the Raiders.

"Open space is nice, I don't know how much you can trust those GPS things," Oldfield joked.

Rapana said he will be better for last week's run as he continues his comeback from a serious hamstring strain.

However, the New Zealand international said the side knows how tough a task they face this weekend, having lost all six of their games against top eight sides this season.

"I was confident I had done all of the rehab I needed to do, probably the cold weather more than anything (was a worry) but I was pretty confident heading into the game," Rapana said of his recovering hamstring.

"Towards the end of the game I got a little line-break and the fatigue started to set in and I started to wonder about it.

"Putting it under fatigue and putting in tough situations where it gets awkwardly, and it gets pout through those certain situations."

Bizarrely, the away side has won the past 10 clashes between the Raiders and Sharks, a record stretching back to 2013. 

"Whenever we play them, it's always been a tough game and whoever wins the middle wins the game so it's a big game for our forwards to lay that platform and muscle up with the middles because they've got a great starting pack," Rapana said.