Gun flanker Sam Greatbatch damaged the AC joint in his shoulder during the second half of Emus' round six slugfest against Forbes.

The loss of Greatbatch adds injury to insult for the men in green, with the club forced to move its huge clash with the defending premiers to Ann Ashwood at Bathurst due to the deteriorating surface at Endeavour Oval.

Greatbatch's omission is offset somewhat by the return of Sam McLean in the second-row, which pushes Simon Badgery on to the side of the scrum.

Emus co-captain Charlie Henley said the loss of the in-form Greatbatch is a significant one, especially ahead of another trip to Bathurst to face the Bulldogs.

"He's the heartbeat of our forward pack, that bloke," Henley said.

"He gets up off the line and he's probably one of the smallest blokes on our team but hits harder than anyone else. He'll be a big loss."

A win over Bulldogs will all-but secure the top spot on the ladder for Pete Bromley's men, giving them the chance to host a finals game in week one, and then potentially a grand final.

The 2020 season will use a top four finals system, with one taking on four and two playing three. Both winners progress to the decider.