Despite his standout NRL form with the St George Illawarra Dragons, 30-year-old Marshall isn't being considered by New Zealand's selectors for the Anzac test in Brisbane on May 1.
Kearney says it is nothing to do with age, nor former captain Marshall's short-lived switch to rugby union last year.
The selectors want to persist with the halves pair of Shaun Johnson and Kieran Foran who steered the Kiwis to last year's Four Nations title and will be named in the squad on Sunday night, injuries permitting.
Kearney is confident Manly standoff Foran has overcome a hamstring niggle but says he will need to prove himself against Melbourne on Saturday.
Even if he doesn't, Marshall won't be considered to add to his 27 tests.
"We've got the halves pairing that we've invested a lot of time and effort and energy into over the last three years. If they pass fit then they'll be picked," Kearney said.
"We've got a couple of options if that's not the case but for this test match, Benji won't be one of them."
Kearney acknowledged Marshall's form had been "very impressive" for a Dragons side who share the top of the NRL table with Brisbane and Melbourne.
He had tried and failed to contact Marshall this week to tell him that his test career isn't necessarily over. He delivered that message to Marshall's manager Martin Tauber on Wednesday night.
"We're never going to close the door on Benji or any player.
"But for this test I've got two guys ... who are both 24 and players who have got all of their football in front of them."
Kearney says he has stayed in close contact with Foran over the past week, along with several other Kiwis candidates who are under injury clouds.
Centre Dean Whare appears to have also overcome a hamstring problem while Kearney says his Penrith teammate Lewis Brown (ribs) is still a chance to play against Cronulla on Sunday despite not being named in their team.
The Test prognosis for Jason Nightingale (foot) was "50-50", according to Kearney, after the experienced wing was omitted by the Dragons.
The coach insists form will be a key plank in his squad selection, insisting he won't stick rigidly with his triumphant Four Nations squad.
He nominated Roosters fullback Roger Tuivasa-Sheck and Warriors prop Ben Matulino as two obvious candidates who are knocking down the door for recalls.
