During his 20-month stint as England boss, Southgate has looked to lower the age of the squad by effectively ending the global careers of Wayne Rooney, Walcott and Joe Hart as well as steadfastly refusing to select Chris Smalling.
Southgate's number one goalkeeping choice for Russian Federation is sure to be broached on Thursday morning, along with questions on the captaincy and composition of his stand-by list. Only two players are over the age of 30, and only one player has more than 38 caps.
Not that it was ever in doubt, but Manchester City full-back Walker missed the news of his call-up when the England manager first tried to reach him.
He named Burnley goalkeeper Nick Pope in place of Hart and called up Manchester City's Fabian Delph, who can play at left-back or in midfield, to take over from Wilshere.
Southgate named his 23-man squad on Wednesday and chose to omit Wilshere, who was also left off the five-man standby list for the upcoming tournament in Russian Federation.
England took to Twitter to reveal their squad for the World Cup in Russian Federation.
Thirty-goal striker Harry Kane, full-back Danny Rose and Dele Alli are among those to secure a place from Mauricio Pochettino's side, while Anfield provides Jordan Henderson and uncapped 19-year-old right-back Trent Alexander-Arnold.
Hart in action during his last England appearance in November
The 31-year-old has 75 caps - more than any other player to play under Southgate - but is absent as a result of an error-strewn campaign at West Ham United.
"We've also had a couple of injuries with Alex Oxlade-Chamberlain and Joe Gomez, which is a huge blow for them personally and disappointing for us".
Danny Welbeck made the squad, despite not being a regular for Arsenal this season.
"We have a lot of energy and athleticism in the team but also players equally comfortable in possession". "We felt the players all needed to be in on merit after their performances this season".
England's World Cup squad get their first chance to play together at Wembley Stadium on June 2 in a friendly with Group D's Nigeria.
On the stand-by list are Burnley goalkeeper Tom Heaton and centre-back James Tarkowski, West Brom midfielder Jake Livermore and Liverpool's Adam Lallana.
Top level EU talks on Iran nuclear deal after US exit
The US Treasury has also said it plans to enforce "secondary sanctions" on Iran that could ensnare European and global companies. Trump's unilateral withdrawal fom the Iran deal would increase tensions in the Middle East and fuel an arms race.