ESSENDON is hopeful it will regain defender Dustin Fletcher and ruckman Paddy Ryder in time for the finals, with both receiving positive news on the injury front.

Fletcher sat out the second half of the Bombers' two-point win over St Kilda on Sunday evening and Ryder most of the last quarter, after picking up hamstring and knee complaints respectively.

While it initially looked as though both were set for lengthy periods on the sidelines, Fletcher could be back in round 22 and Ryder the first week of finals, should the Bombers make it.

"With Dustin, it looks like being better than first thought. The scans look like they're clear, and we'll assess him as the week goes on," Knights said on Tuesday.

"He obviously couldn't complete the game last week so he'd have to improve enormously for me to select him.

"[With Ryder], it's also better than we first thought. I think he's strained or hurt a popliteus [muscle] behind the knee, but he's going to be shorter rather than longer as well, preferably one week, but maybe two or three."

Knights confirmed Courtenay Dempsey would miss two to three weeks after suffering a grade one hamstring strain in the same game.

Matthew Lloyd [bruised heel] and Jason Winderlich [back] face fitness tests later in the week to see if they're set to make the trip west to play Fremantle at Subiaco on Sunday.

Knights said Darcy Daniher, Cale Hooker, Hayden Skipworth, Heath Hocking and Leroy Jetta were all playing well in the VFL and would be suitable replacements.

"There are a number of guys down there that are putting up decent performances, and we'll have a look at all of those guys this afternoon and Thursday and finalise our side," he said.

The Bombers will look closely at including Hooker as a back-up for Tom Bellchambers, who will move up to No.1 ruck spot following Ryder's injury.

Midfielder Bachar Houli has joined Scott Gumbleton (back), Jason Laycock (foot), David Hille (knee) and John Williams (shoulder) as players unavailable for the rest of the year, after fracturing his fibula at training last week.

Scott Lucas has also announced his immediate retirement from football and won't take any further part in the Bombers' 2009 campaign.

Knights said his side would need to match the intensity it showed against St Kilda to beat the 15th-placed Fremantle this Sunday.

"They've been very good on their home ground," Knights said. "They've played very well there this year, so we've going to have to play to at least the standard we played against the Saints to get the job done, and I hope the players realise that."