The 2014 premiership-winning five-eighth has been linked with a move to either the Roosters or Dragons after four seasons at Redfern.
Keary said as recently as last Tuesday that his future would be decided in the coming weeks, and it appears certain that the next chapter of his rugby league career won't be with the Rabbitohs.
Speaking at Redfern Oval ahead of their crucial clash against the Panthers on Friday night, Rabbitohs players expressed their sadness in seeing their teammate leave the club.
"It's his last year now so we've just got to make the most of the time that we've got together," Tom Burgess said.
"He's a great teammate and I'm looking forward to continuing the year with him."
Current South Sydney pivot Cody Walker echoed Burgess's sentiment.
"He said his future doesn’t lie here at Souths," Walker said. "It'll be sad to see him go but I'm really looking forward to finishing the year with him."
Keary's grand-final-winning teammate Alex Johnston added: "I love playing with Luke. He's a great bloke and a great player. It'll be sad to see him go."
The Rabbitohs have more pressing things to worry about at the moment, as they sit in 13th place on the NRL Telstra Premiership ladder following three straight losses.
Burgess said the mood in the camp was still positive despite the slump and said the team needed to fix the "fundamentals" quickly if they wanted to turn their season around.
"When you have a few losses you've got to keep your spirits up, and that's one thing that we're doing," the Englishman said.
"You've got to stick together as a team and keep working hard on the things that are going to help our performance. We just need to get the little things right this week and the results will take care of itself.
"It's not the most complex game in the world. If you hold onto the ball and don't give penalties away then you're going to give yourself a good chance of winning."
The Rabbitohs conceded 10 penalties in their last-start loss to the Eels and only completed at 70 per cent in the 30-12 loss at ANZ Stadium.
Walker said that while the team had shown glimpses of their best on Friday night, he felt the overall performance wasn't good enough.
"The effort's there. We just can't seem to put it together for 80 minutes," he said.
"I think it's individual concentration levels and focus at those moments in time. We're not holding the ball for long periods of time. We're dropping it and letting other teams get the ball."