But newly appointed Test bowling coach McDermott says the attack will need to be firing on all cylinders if they're to steal the urn back from England this summer, and reinvigorating Siddle is one of the first items on his agenda.
QUICK SINGLE: McDermott back in the fold
After quitting his post as a national assistant in May last year, McDermott returns in a more specialised role as Test bowling coach, with incumbent Ali de Winter shifted across to oversee Australia's limited-overs bowlers.
McDermott has just over a month to work his magic before the first Test starts in Brisbane, with the 48-year-old's goal to get four-to-six quicks, including Siddle, hitting their peak at the same time.
"I would like to get him (Siddle) up just a little bit higher with his consistency," said McDermott.
"We've got to have four-to-six guys bowling well from a fast bowling point of view to bowl in conjunction with our spinners ... we've got to make sure they're all firing.
"I'd just like to talk to (Siddle) about a few things I've noticed over the last couple of months, and the same with a number of the other bowlers I've been watching on TV around the place."
Siddle took 17 wickets at 31.58 in the Ashes, the fifth best from either team for the series, and he's still ranked sixth in the world.
However, he took just one wicket in the final two Tests.
Siddle's rise to premier fast bowler a couple of years ago was heavily influenced by McDermott, and the former Australian tearaway is confident of once again making an impact.
McDermott has also been impressed with the transformation of Mitchell Johnson, and is eager to see how the left-arm quick adjusts to the red ball when he returns from Australia's one-day tour of India.
"He's changed his run up, he's well balanced ... he's getting through the crease and his arm is higher than what it used to be," McDermott said.
"He's bowling anywhere between 145 and 153km/h over the last couple of months ... and, if you're up around those figures and moving the ball a little bit either way, it's a handful and certainly his bouncer will be a handful as well.
"Obviously there's Ben Hilfenhaus who is back in the fray, fully fit."