Jason Ashby is set for an extended period on the sidelines after hurting his knee during a VFL practice match on the weekend.

The 21 year old had enjoyed an injury free build up to the season before sustaining a minor ankle injury in the NAB Challenge game against Carlton and then this latest setback during Saturday’s match.

“Jason went down with a knee problem,” High Performance Manager Justin Crow said.

“We had that scanned and it turns out he had a small patella dislocation, or knee cap dislocation.

“We’re looking at a couple of months out with that but sometimes players do a little bit better so there is a bit of hope there for Jase.”

The Bombers are hopeful Jayden Laverde will be available for round one against Gold Coast but his recovery from an ankle injury has been slower than expected. 

“Jayden still hasn’t run yet – we’re hoping he’ll start running in the next couple of days,” Crow said.

“So that starts to put a little more doubt over his availability for round one but we’ve still got a little ray of hope that he might get up.”

Darcy Parish and Ryan Crowley are making better progress and will join in training this week.

The Dons match against the Eagles brought an end to their NAB Challenge campaign.

Crow is happy with the team's physical preparation leading into the season opener against Gold Coast next week.

“We’re really well placed - we’ve had a really great conditioning hit in the last two weeks in the heat,” Crow said. 

“If we’d had the choice between a hot day  and a cold day we would have picked hot days. 

“A lot of our guys had really high durations in high heart rate zones over there in Perth and we think we’ll benefit from that over the next couple of weeks.”