That's the verdict of former Ireland defender Damien Delaney, who has told the Sunday World that Southgate needs to protect his vulnerable centre-back pairing if England are to have any hope of reaching the latter stages in Qatar.
Tonight's last-16 game against Senegal could provide the first big test for England as they eye up World Cup glory, with Virgin Media Sport pundit Delaney telling us that their attacking ambition will be stunted by their defensive weakness.
There has been a clamour in the English media to get Marcus Rashford and Phil Foden into the England team that could also feature captain Harry Kane, Raheem Sterling, Jude Bellingham and Bukayo Saka.
Yet former Crystal Palace and Ireland defender Delaney believes Southgate made the decision some time ago that he would not release his attacking stars in a side lacking top quality central defenders.
"Southgate gets a lot of stick for the way he sets his team up, but I don't think he has any choice than to be cautious," Delaney told the Sunday World at Virgin Media’s ‘Gamers are Athletes’ campaign.
"England have lots of fantastic attacking talent, but getting them all in the team means going with a flat back four and one holding midfielder.
"The trouble is, they don't have a centre-back who can be relied upon to deal with teams hitting them on the break if they have that set-up.
"As we have seen at Manchester United, Harry Maguire cannot defend when he has open space in front of him and an attacking player coming his way in a one-on-one.
"He needs to be insulated and have players around him to offer protection and that is very much in Southgate's mind when he puts players like Declan Rice and Jordan Henderson in front of him.
"If you look at how England got to the finals of the Euros last year, they basically played with a back five, two holding midfielder and three attacking players.
"When you have guys like Harry Kane in the team, you will always have a chance to get goals, so Southgate feels he needs to be cautious and he is happy to take the flack he gets if it produces results.
"In a World Cup, one or two mistakes from a centre-back ends your tournament, so he is doing everything possible to avoid that scenario."
Marcus Rashford has emerged as the stand-out performer for England at this World Cup with three goals so far and Delaney believes the Manchester United man has forced his way into the side.
"Southgate has been loyal to players like Mason Mount and Raheem Sterling, but Rashford has done enough to get into the team now," he continued.
"When England play with that defensive mentality, Rashford gives them a real outlet with his pace and finishing ability.
"Kane will play against Senegal and you can only play two more attacking players in the set-up Southgate will go with for the knock-out stages and Rashford may have nudged himself ahead of Sterling for one of those roles now."
France may be lying in wait for England if they get through to the quarter-final next Saturday, with Delaney expecting that game to expose the weak spots Southgate is trying to cover up.
"I would be amazed if England's defence was good enough to stand-up to Kylian Mbappe and France if they get that far," he added.
"They will need an awful lot of luck to get through games like France and maybe Brazil after that because they will get to that defence and test Maguire and Stones.
"Brazil are my favourites from what I have seen so far, with France not far behind and Portugal are my tip to have a good run.
"Cristiano Ronaldo has been making headlines for the wrong reasons in recent weeks, but Portugal have a good team around him and they could go close.
"I had to laugh the other night when Ronaldo was claiming a goal he didn't get a touch on, but that's what he is all about. It’s always about him.
"You need to treat players of that stature a little differently and allow them to get away with things others never would.
"That might explain why Ronaldo I struggling to find a top European team that would take him as a lot of managers wouldn't fancy the hassle that comes with him.
"Despite all of that, he is still a player who can win you a game with a flash of genius and that's one reason why I feel Portugal could have a chance to get to the latter end of this World Cup."
Delaney spoke to the Sunday World as part of Virgin Media’s ‘Gamers are Athletes’ campaign, which saw Irish football legends David Meyler and Stephanie Roche team up with Team WYLDE Athletes Tyrone Ryan and Ciaran Walsh and compete in a live FIFA battle.