Trent Alexander-Arnold was at Wembley on Saturday, but he wasn’t on the pitch. Perhaps it is the story of his England career. The temptation is to call it stop-start, but the stops have outnumbered the starts, with a mere 23 caps in almost six years since his debut.

If Gareth Southgate has been criticised for giving a generational player a watching brief, he was faultless at the weekend. Alexander-Arnold was injured. That he chose to travel south and support his teammates as England lost to Brazil reflects in part on the atmosphere Southgate has created.

It also shows that the Liverpool vice-captain remains keen to succeed for country as well as club.

“He wanted to come to the game, he’s obviously in the latter stage of rehab with Liverpool so it wasn’t quite as easy for him to dip in like Luke Shaw did,” said Southgate. Alexander-Arnold’s knee injury has provided a problem for the England manager. He wanted to experiment with a wonderful passer in midfield; now the danger is he has too little grounding in the role and the international team before Euro 2024 to render him a starter.

“The midfield thing we’ve seen, but we’ve missed two opportunities with September and now this one. That is really frustrating because there’s so much that’s unknown about it at the minute,” Southgate said. “I’ve liked the idea for a long time but we’re going to be trialling it when we haven’t seen it in a really high-level game. So we’ll just have to see where we can go with it.”

Southgate has long felt Alexander-Arnold has the ability. What he lacks, even as he inverts more into the middle with Liverpool, is the experience of being a midfield starter. “It’s such a specialist position,” Southgate said. “There’s a huge difference between playing at full back and popping into midfield and playing in there, starting in there, in and out of position in the game. Receiving with your back to goal, so there’s a lot to that. We’re just going to have to see.”

It feels an unfinished project. Southgate first picked Alexander-Arnold in midfield against Andorra in 2021 – Jurgen Klopp then expressing surprise he picked “the best right-back in the world” there – before his reinvention with Liverpool gave the England manager further reasons to take the Merseysider out of a competition with Kyle Walker and Kieran Trippier that he was losing and into a position where there could be a vacancy.

Arguably the most exciting, most gifted England midfield consists of Declan Rice, Jude Bellingham and Alexander-Arnold. For now, however, it remains more of a concept than a reality. They have never begun together as a central trio.

And a recurring theme of the last 18 months has been Southgate’s search for his third man, for the player to complement Rice and Bellingham.

Kalvin Phillips’ terrific Euro 2020 generated loyalty. Some felt Southgate showed too much as he lingered on the fringes at Manchester City but the first-team football that was supposed to enable the former Leeds player to restate his case instead demolished it, Phillips’ wretched form for West Ham leading to his omission from the international squad.

Jordan Henderson was the man in possession, a fine World Cup followed by terrific performances in the summer thrashings of Malta and North Macedonia, when he dovetailed well with Rice and Alexander-Arnold. Yet then came Saudi Arabia, a sizeable dent to Henderson’s reputation but also the sense he has lost some of his running power in lesser leagues. Henderson can seem further proof of Southgate’s stubbornness, of his willingness to overlook club form for those who have served him well in the past.

If Phillips’ fate shows he does draw distinctions, that his patience is not infinite, the veteran may benefit from the inability of others to nail down the third spot in midfield.

Conor Gallagher brought honest endeavour but too little else in Saturday’s defeat to Brazil. The sense is that, while he provides what Moises Caicedo and Enzo Fernandez lack for Chelsea, he is yet to prove such an invaluable ally at international level. Kobbie Mainoo can offer more excitement and brim with more potential but, with a mere 15 league appearances to his name, he is a rookie.

So, in another sense, is Alexander-Arnold the midfielder but whereas England’s clash with Belgium could give a chance to Henderson, to Gallagher or to Mainoo, it will not to the injured Alexander-Arnold. And so Southgate will have to pick his Euro 2024 squad with some of his questions still unanswered, with potentially England’s finest midfield still only an idea.