ESSENDON defender Mitch Brown's season is in doubt after suffering another ankle injury at VFL level on the weekend.

Brown was playing his second VFL game since returning from a long-term ankle injury he sustained late in the Bombers' round six loss to Melbourne.

But in the final minute of Saturday's VFL loss to Richmond, Brown had another ankle injury and is set for at least six weeks on the sidelines.

Match preview: Collingwood v Essendon

"He got caught up in a tackle and the opposition player's full weight went through his ankle…it's really bad news for Mitch, he's seeing the specialist today," Essendon high performance manager Justin Crow told the club's website.

"[There's] a chance a band is put around his (partially torn) syndesmosis for some extra stability. Whether he has that surgery or not won't affect his prognosis.

"He's going to spend two weeks off his feet and look to be back training at the six-week mark.

"There's a chance that, all going well, Mitch will be available around that final game of the year. Obviously these can be a bit variable, but potentially he'll have that band put in and then he'll progress upwards from there with a little bit of light at the end of the tunnel."

It is a further blow to Essendon's defence, given they are at least two weeks away from having Patrick Ambrose available from his quad strain.

Small defender Ben McNiece is also on the sidelines. McNiece, who made his AFL debut on Anzac Day, suffered from a whiplash injury through the pre-season and had a collision at training two weeks ago. That "re-aggravated" those issues in his beck.

The club is hoping McNiece can return to training next week.