Elsom will miss four to six weeks due to a syndemosis injury.
The news comes as a blow to Brumbies fans as Elsom is widely expected to leave the Super Rugby franchise at the end of the season.
Elsom returned from a six-month hamstring injury lay-off against the Force last Saturday, only to get injured in what looks to be his final game for the Canberra side.
Brumbies coach Tony Rea says Elsom's focus will now turn to September.
"I don't think we'll see him again," Rea said.
"He just needs to get himself ready for the World Cup now.
"It's just disappointing for him - he's worked so hard to get back and he only got himself back for one [game]."
Tags: sport, rugby-union, super-14, australia, act, canberra-2600 First posted May 25, 2011 10:43:00