Scott Boland is on standby.
Coulter-Nile should be on drinks duty in Hobart, where James Pattinson is fully expected to play in place of Starc.
Boland should be playing for Victoria in the Sheffield Shield round starting Sunday.
However, there are few certainties regarding Australia's attack as Marsh attempts to recharge his depleted pace battery.
Peter Siddle's sore back was scanned on Tuesday, while team medicos have been worried about Josh Hazlewood's workloads since the first Test against New Zealand.
Hazlewood is in career-best form but will almost certainly be rested from at least one of the upcoming Tests against the West Indies.
It is a headache for Marsh, made all the more bothersome by Pat Cummins' back stress fractures and this year's retirements of Johnson and Ryan Harris.
Even Jason Behrendorff, the leading young left-armer in the land, is injured.
"They're not even sure whether he'll be out for the rest of the season," Marsh said.
"We've got to get on with it.
"We've got to have a battery of 10 fast bowlers. I know everyone out there looks at me as if I'm an idiot when I say that.
"But ... they just don't get through a lot of Test matches in a row."
Coulter-Nile has played 13 ODIs and 11 T20s for Australia, with express pace among his greatest assets.
He only recently resumed bowling after a shoulder injury and has a history of hamstring trouble.
The West Australian hasn't played first-class cricket since the Shield final in March.
"We're not too concerned about that," Marsh said.
"It would have been good if he had been playing Shield cricket the whole season and taken 40 wickets.
"But we don't get too many of them so we'll go with our gut feeling."
Coulter-Nile has been on the selection panel's radar for "a long time".
"Once Mitchell Starc went down I think everyone's mind went straight to Nathan Coulter-Nile," he said.
"The two Mitchells - one retiring and one being injured ... we do need a bit of pace.
"We're worried about players breaking down but we've got to trust medical staff, we've got to trust the players."
Jackson Bird, who played the most recent of his three Tests in the 2013 Ashes, is back to full fitness but wasn't seriously considered.
"We don't think anyone is unlucky in this selection," Marsh said.
Andrew Fekete was picked for the postponed tour of Bangladesh but recently dropped by Tasmania, a pointer to his current form struggles.
It seems like feast has become famine regarding the nation's pace stocks - traditionally a strength.
Marsh disagreed.
"On the depth chart we've got 20 fast bowlers that we rate a chance of playing (for Australia)," he said.
Australia Test Squad: Steve Smith (captain), David Warner, Joe Burns, Adam Voges, Mitchell Marsh, Shaun Marsh, Peter Nevill (wicketkeeper), Peter Siddle, James Pattinson, Josh Hazlewood, Nathan Coulter-Nile, Nathan Lyon.
- AAP
