Brumbies coach Dan McKellar has already set his sights on a player to fill the void left by Mann-Rea after he suffered a suspected anterior cruciate ligament tear.

McKellar has to defy a 13-hour time difference from Argentina this week as he looks to shore up his squad on the run to the Super Rugby finals.

The Brumbies are holding onto a shred of hope Mann-Rea has avoided an ACL tear as he prepares to go for more scans upon his return to Canberra.

Whether the off-contract 38-year-old is able to battle back through nine months of rehabilitation to return remains one of the biggest questions.

Injury would be a cruel way to bow out for the former Wallaby, who Brumbies chief executive Phil Thomson says is among the most respected faces in the club.

"They've just got to get scans done properly, obviously it is a suspected ACL but we will get him scanned up and see someone here before we know exactly what the diagnosis is," Thomson said.

"We will give him time to understand what is the next step and then we will sit down and have a chat with him around his future. Realistically, he is 38 years of age so it is probably close to the end for him. It's going to be a tough one.

"I haven't spoken to him so I will give him a bit of time to sort out the medical side of things, and then we will have a chat to him after that."

An announcement on Mann-Rea's replacement in the squad will ideally come this week before the Brumbies return from Argentina.

Connal McInerney has joined the squad on tour to take Mann-Rea's spot on the bench behind starting hooker Folau Fainga'a.

"We've got a couple of options, so Dan has been in contact with Chris Tindall, our high performance manager, about a list of names at the moment," Thomson said.

"There will have to be somebody who comes in at some stage. Hopefully within the next 24 to 48 hours we will have someone. If not we will go to a plan B."