Trent Alexander-Arnold has been told to get "more serious about his defending" by Gary Neville.
Neville believes the Liverpool full-back's recent England snub might foreshadow what happens ahead of Euro 2020 this summer.
Alexander-Arnold was surprisingly left out of England's squad for the recent World Cup qualifying victories against San Marino, Albania and Poland, with Kyle Walker, Kieran Trippier and Reece James the right-backs chosen.
Gareth Southgate's decision has led to scrutiny about where Alexander-Arnold fits into the England boss' plans ahead of the European Championships, and Neville has raised the prospect of the 22-year-old being left at home.
The former Manchester United and England defender said on Sky Sports: "I don't think he will include him, I think leaving him out of the March and April friendlies are a precursor to leaving him out in the summer.
"I don't think he would have just dropped that bombshell, I think he's getting everyone used to the fact that this incredible talent is maybe not going to a tournament, unless Walker, Trippier or James get injured.
"When I watch Trent Alexander-Arnold, the opposition manager will think 'attack down that side'. He has to become more serious about his defending.
"In a one-off game in a tournament, a quarter-final or a semi-final, who are England going to be playing? They're going to be playing Germany, Belgium France or Portugal.
"Who's he going to be playing against? Eden Hazard, Leroy Sane, Kylian Mbappe, Diogo Jota or Cristiano Ronaldo. Who do they want to play against? They'll say 'I'll let Trent go on, he'll leave space in behind, I'll have Trent'.
"I trust Gareth with this England squad. He's been to so many tournaments as a player, he's the only living manager that has got England to a World Cup semi-final and he's got to win one-off games that will be decided in moments.
"I think the reason he won't take him is he's there to win a tournament and I think he'll take the players he can trust like Walker, Trippier, maybe James because he's got more power and strength to handle an Mbappe or Ronaldo."
While Neville insisted he would personally select Alexander-Arnold if he were in charge, the debate turned heated with fellow Sky Sports pundit Jamie Carragher.
The former Liverpool and England defender said: "If you pick Kieran Trippier ahead of Trent Alexander-Arnold, that's embarrassing."
