Speaking on the eve of his side's season-ending friendly against France, Southgate confirmed Harry Kane would retain the captaincy and promised goalkeepers Tom Heaton and Jack Butland 45 minutes each in place of Joe Hart - while also announcing the latter was still his 'number one'.
But it was his revelation that Stones, Manchester City's £50m centre-half, was being considered for a switch into unfamiliar territory that piqued most interest.
Stones was edged out of the team that drew 2-2 with Scotland on Saturday by Chris Smalling and Gary Cahill but Southgate feels he has the requisite ball-playing skills to operate further up the pitch and may hand the 23-year-old a first opportunity to test drive the anchor role at Stade de France.
That is by no means guaranteed, with a back three also considered, but is seen as a live option in a squad that looks light in the engine room, where Eric Dier and Jake Livermore are the only specialists in a 23-man squad.
"Do I believe he can play that role? Absolutely," said Southgate.
"I think he could do that. We had a look at that in training in fact. He's a player who is very comfortable receiving possession, he has all the attributes to play as a holding midfield player.
"He obviously hasn't done that yet really, so that's a decision we have to make.
"I also think we want defenders who can bring the ball out and show composure. I think he could do either of those jobs."
Southgate knows more than most about the demands of moving between two positions, starting his career in the centre of the park before making his name as a centre-half.
He infrequently returned to midfield duties for England, at Euro 96 by Terry Venables then - less successfully - as Kevin Keegan's Three Lions lost the last game at the old Wembley to rivals Germany.
"When Terry did it, it was genius," he added with a smile.
It is a lot to ask of a player who, despite his monster transfer free, is still developing key parts of his game, but Southgate is not worried about that.
"John has huge potential. Defending is a skill you learn and he'll learn a lot with a coach (City boss Pep Guardiola) asking a lot of him with the ball.
"He knows the belief we have in him as a player."
Scotland vs England player ratings
Scotland vs England player ratings
1/22 Craig Gordon – 4 out of 10
Will be disappointed with himself. Should have saved Oxlade-Chamberlain’s strike, which itself stemmed from him misjudging a backpass from Tierney.
2/22 Christophe Berra – 6 out of 10
A decent display and cannot be blamed for either of England's goals, though could have organised his backline better.
3/22 Charlie Mulgrew – 5 out of 10
Guilty of ball-watching for England’s late equaliser and losing track of Kane, though could have done with a shout from Robertson.
4/22 Kieran Tierney - 7 out of 10
Impressive from the youngster. One goal-line clearance, one vital block to deny Rashford a clear shot at goal, but let himself down on the Oxlade-Chamberlain goal.
5/22 Ikechi Anya - 6 out of 10
Had an opportunity to get at a nervy Walker but did not take it.
6/22 Andrew Robertson – 6 out of 10
Troubled England’s right flank, though benefitted from Rashford’s hesitancy to track back. Mix-up with Mulgrew cost his side.
7/22 James Morrison – 5 out of 10
Hampered by an early knock, failed to find his rhythm in the game. Substituted at half-time.
8/22 Scott Brown – 6 out of 10
Took only three minutes to pick up a yellow card. If only he had put as strong a foot in on Oxlade-Chamberlain in the build-up to the goal.
9/22 Stuart Armstrong – 6 out of 10
Showed neat touches around England’s box and his movement troubled red shirts at times, but should have held the ball up better before Kane's equaliser.
10/22 Robert Snodgrass – 5 out of 10
Scotland needed a performance from him, but he was quiet and ineffective, much like he was throughout the second half of the season.
11/22 Leigh Griffiths - 9 out of 10
Two incredible late free-kicks and both deserved. Suffered from poor service but did not let that deter him, pressing England’s backline throughout.
12/22 Joe Hart – 4 out of 10
Largely untroubled until the late goals, both of which he should have saved. Questions have to be asked whether he is still England’s best ‘keeper.
13/22 Kyle Walker – 5 out of 10
Poor. Penalty call against him for the trip on Griffiths could have gone either way, but it was just one of several mistakes.
14/22 Chris Smalling – 6 out of 10
Recovered from a nervy start that included one horribly shanked clearance over his own goalmouth.
15/22 Gary Cahill – 7 out of 10
More assured than his defensive partner for the majority of the game, until that reckless challenge to concede first fatal free-kick.
16/22 Ryan Bertrand – 7 out of 10
Bright down the left, especially going forward.
17/22 Jake Livermore – 7 out of 10
His selection raised the odd eyebrow but, particularly in the first half, he was England’s most composed player.
18/22 Eric Dier – 5 out of 10
Paled in comparison to Livermore on a real off-day for the Tottenham midfielder. Picked up a needless yellow card, too.
19/22 Marcus Rashford – 5 out of 10
On his first competitive international start, a display that suggested he remains only an impact player for now. Did not take to his role on the right flank.
20/22 Dele Alli – 5 out of 10
Totally failed to get going, looking tired and cumbersome at times. England's best player on his day, but that was not today.
21/22 Adam Lallana – 7 out of 10
England’s best attacking outlet and particularly came the fore after half-time, once he began to find more space in Scotland’s half.
22/22 Harry Kane – 7 out of 10
Missing his usual composure in front of goal but found it when it mattered. A simple finish but one he needed to make.
Another player who can count on that same belief is Hart. His inability to keep out two Leigh Griffiths free-kicks at Hampden Park attracted plenty of debate and two of his challengers for the gloves will now get a chance to showcase their credentials.
Hart's uncertain club future, unwanted by Manchester City and as yet without an apparent destination, means his status may yet be revised by the time of the next international get together but, for now at least, Southgate is clear.
Asked if he knew his number one goalkeeper, he did not miss a beat before answering: "Joe Hart."
He added: "Next season we don't know who will be playing at which club, who will be in form. But Joe has been excellent for us. The goals on Saturday were the first he'd conceded in qualifying, and we owe him for (a man-of-the-match performance in) Slovenia.
"His contribution around the group has been excellent since I've been manager. That said, I don't want anyone to feel completely comfortable in (a) position because that's not helpful. We want competition for places."