The 26-year-old Scot, who has been seeded No.4 for the first grand slam tournament of the year in Melbourne this fortnight, has played down his chances of celebrating a third major victory, as to date he has completed just four competitive matches since returning from back surgery in September, a run that includes defeats by Jo-Wilfried Tsonga and Florian Mayer.
Cahill, part of the adidas coaching team as well as a pundit for broadcasters ESPN, agrees that such a prospect is improbable, but not entirely impossible if he can negotiate his way into the second week with a minimum of physical discomfort.
"I think that what Andy said is 100% correct," said Cahill. "Andy is the type of player who needs a lot of fitness, a lot of matches to be feeling his tennis legs on the court. At the moment, because of his back operation, he hasn't been able to do that so I think it is a logical thing for him to state coming into the Australian Open.
"He is setting his sights on being close to 100% by Indian Wells and Miami, the two bigger hard-court tournaments in the States before the clay court season begins," added the Australian, the man who first put Murray in touch with his coach Ivan Lendl. "To come off surgery, have a few weeks training, play a few tennis matches, then win the Australian Open is unrealistic. Andy is being sensible about lowering expectations, not only his expectations but everyone else's as well.
"We will get a good indication about how he is after the first couple of matches here in Melbourne. But the big X Factor, so far as Andy is concerned, is that, a couple of years ago, having been through what he has been through in the last couple of months, I would have given him no chance at all of winning the Australian Open. But now he knows how to win majors.
"Over the last 18 months he has been US Open champion, he is the Wimbledon champion and the Olympic gold medallist, so if you put Andy Murray in the second week and give him a path through that second week which isn't going to be overly taxing on his body, then things change dramatically. He becomes a factor again. It is just those first two or three matches which will be very crucial for him to make sure that he protects his body and doesn't use up too much gas."
Murray's decision to thrust himself into action is the opposite approach to that taken by Rafa Nadal 12 months earlier, the Mallorcan having declined to rush back to play in Melbourne. He, though, subsequently pieced together an inspired run which took him all the way back to world No.1 by the year's end.
The Scot's preparation for the event will conclude with an exhibition match against re-born home favourite, and recent Brisbane Open champion, Lleyton Hewitt in Kooyong.
"As disappointing as it was for him [Nadal] to be missing the Australian Open," said Cahill. "It may have been a huge blessing in disguise for him not to come back and put his body through the rigours of playing best of five sets straight away. Andy has played a couple of tournaments so it is not quite the same, and he wasn't out for quite so long, but Nadal is a different athlete to Andy.
"Andy is very in touch with all the little niggles and problems he has with his body, he is not the kind of guy who can shake it off the way that Nadal can. He hasn't had too many matches, and was a little bit disappointing in Doha, I believe. He needs matches, that is why he is playing an exhibition against Lleyton Hewitt on Friday to get that one extra match before the tournament starts."