When the Ashes squad was originally announced, national selector George Bailey had indicated it was possible that both allrounders could play together. "That's a potential, absolutely," he said. "If that's on the cards, it would be exciting times if you could start to squeeze in two or three allrounders into your top six if they were batting well enough."
However, despite the all-round performance in the third Test, Marsh himself was not so sure of that happening. "I don't think there is [a chance of both him and Green playing in the same XI]," he told cricket.com.au in the aftermath of the loss at Headingley. "Unfortunately, there's not, [and] that's all right."
But Pat Cummins acknowledged that Marsh was tough to leave out. "Yeah, it's possible," Cummins said of playing both allrounders. "But, I mean, it was a pretty impressive week, wasn't it?"
So is there a way Marsh and Green can play in the same team? Here are a few options.
The big one: drop David Warner
However, it's only one game ago that he played a crucial role in Australia's victory at Lord's, making 66 in the first innings and combining for opening stands of 73 and 63 alongside Khawaja in some of the toughest batting conditions of the game under cloudy skies.
Speaking following the second day at Headingley, McDonald lauded those performances by Warner, but while talking again after the loss, he stopped short of guaranteeing Warner his place for Old Trafford.
"I think we've got everything to consider in terms of Mitch Marsh coming in - what the balance looks like, [and] our allrounders - and there will be an assessment of the players at the back end of this Test," he said. "We've got an extra batter who's put his hand up, and we'll have to consider the options ahead."
Can Marsh and Green play together?
2.0K votesYes - leave out David Warner
Yes - leave out Marnus Labuschagne
Yes - leave out Todd Murphy
No - Green will have to wait to return
No - Green replaces Marsh
There would be a cascading effect if Warner was left out, which could potentially mean destabilising the XI, as someone would need to open. Travis Head could be an option after filling the role in India, although those were vastly different conditions, and he remains key at No. 5. Labuschagne could go up one spot, but he's not looking in the best of form at the moment. It was even put to McDonald whether Marsh could open, as he has recently done in ODIs.
"He did pretty well down the middle order," he said. "To put him up to open in English conditions would probably be something we haven't discussed yet. But we do have some time between now and the next Test."
Is Labuschagne vulnerable?
It seems an absurd question to ask, but for the first time since he returned to Test cricket during the 2019 Ashes, Labuschagne is going through, by his high standards, a lean run which has brought just two half-centuries in his last 21 innings.
He has looked out of sorts on this tour, where he got a working over from India's quicks in the World Test Championship final before nicking off to Stuart Broad's outswinger at Edgbaston. At Headingley, his slog sweep to deep midwicket was the moment where England got themselves back into the match. Labuschagne has, however, reached double figures in seven of his eight innings on the tour.
"I think the starts are the important part," McDonald said. "If you can get a start, you can show your method can stand up to the challenges. Maybe he's trying to expand at certain times when he doesn't need to, and that's a conversation he'll be having with himself and the coaches. But I think if you're not getting starts, it's more of a concern."
Leave out the spinner
Murphy claimed Ben Stokes in the first innings but not before being dispatched for five sixes and, significantly, only bowled two overs during England's chase - one before lunch and then another when only another 30 runs were needed.
"We like to have a balanced attack, and it gives you options," McDonald said. "You can take pace out of the game and you become one dimensional - whether it be with the right-arm bowlers or just pace bowlers in general - without the ability to turn to a spinner. We'll have to assess that, but as it sits at the moment, we do like to have the spinner in the team."
Maybe, at the end of the day, they can't
So it could back come back to what Marsh believes. He and Green can't play in the same team. The one other factor to consider is that before his injury, Green had not found his top form on this tour either. His batting average after three Tests - including the WTC final - is 19.16, while his bowling average is also a very high 45.60. His biggest impact arguably has been while fielding in the gully region.
And Green does not have to come straight back. For all that he is tipped to be a generational star, it is rare that a young player goes through the early stages of a career with being omitted somewhere.
"There's not a straightforward answer really," McDonald said. "Cameron Green is important to the structure of the team as well, with his all-round capabilities. He's going to be fully fit and available for Manchester, so there's nothing to hide there. We've got a decision to make. It's going to be tough."
Andrew McGlashan is a deputy editor at ESPNcricinfo