Essendon defender James Gwilt has undergone surgery on his knee and appears set to spend the rest of the season on the sidelines.

Gwilt hurt his knee during the match against Richmond on Saturday and spent the majority of the second half on the bench.

The Club was awaiting the results of the surgery before confirming  how long Gwilt be will out for.

“James has got an injury to the cartilage in his knee – the meniscus,” High Performance Manager Justin Crow said.

“He’s been in for surgery this morning with Julian Feller.

“We’ll be waiting for the outcome of that surgery before knowing what’s going to happen for the rest of the year.

“It’s just arthroscopic surgery but given there is only six games to go, we’re a bit unsure where that leaves us.”

In better news for the Bombers, Nathan Grima is a chance to return this week.

The 30-year-old played two senior games earlier this year, but hasn't featured since round eight because of a hip complaint.

“Nathan trained really well today and he’ll train again on Thursday,” Crow said.

“He’ll make a strong case to play this weekend.”

Mathew Stokes has missed the last two weeks with a groin problem.

The premiership player is expected to spend at least another week on the sidelines. 

“He’s making small improvements, we’re going to try to get him back out training hopefully later this week to see how he goes, so to some extent it’s still up in the air,” Crow said.

Mark Jamar is making faster than expected progress in his recovery form a hamstring injury.

The All-Australian ruckman suffered the injury against West Coast last month.

Subsequent scans showed some tendon damage, but Jamar is close to resuming training. 

“Mark Jamar is progressing brilliantly for the type of injury he has,” Crow said.

“He’s back running at good pace.  He’s looking to integrate back into training early next week.

“We’d say he’s ahead of schedule.”

Ryan Crowley (26 possessions) and Jonathan Simpkin (19 possessions) made successful returns from hamstring injuries in the VFL last week. 

Both players pulled up well and will be available for selection this week.

“Really happy with both of those guys, both had a really good return with really good running output in their games,” Crow said. 

“They’ve done some training today and they’re back in the group as per normal.”