"When I read the voicemail that it was him (Eales) calling, I thought it was a bit of a joke, so I called him back and it was him," Dempsey told Fox Sports.
"He called me back three or four times throughout the rehab process to check in on me.
"That window when we (the Waratahs) were supposed to play the Reds — but didn't make it — he called to check up and see what was going on, and obviously I was in a pretty dark space then, he helped me get through that."
The Australian National Rugby Championship competition gave Dempsey an immediate pathway back into the Wallabies system, with six matches for the Sydney Rays and a phone call from Wallabies coach Michael Cheika guiding his way back to the top level.
"He called me to see how my mindset was and I just expressed some personal concerns about not only my long term health but also my short term, and he obviously took that on board and agreed with that.
"He wanted me to come on this trip and I definitely wanted to take up the opportunity, if it was the best thing for me.
"We used the last couple of days in Sydney to get back on track, I got the green tick and we're all good."
Now back with the Wallabies and preparing for a clash against the All Blacks this weekend in Japan, Dempsey will battle with former Crusaders forward Pete Samu and uncapped Jed Holloway for a spot on the bench.