Cole Palmer, Phil Foden, Trent Alexander-Arnold and Harry Maguire are just some of the stunning names to miss out on England's World Cup squad this week.
This is whilst van Toney, Djed Spence, Kobbie Mainoo, Eberechi Eze, Noni Madueke, Jarell Quansah and John Stones are notable inclusions in Thomas Tuchel's 26-man group.
The World Cup squad was always going to be controversial, but the huge names left out has led to backlash against Tuchel who will lead the side into the tournament next month.
Speaking to talkSPORT, Walker revealed that three players who were left out have left him scratching his head. This includes his former teammate Foden, who rarely got his chance under Pep Guardiola this season.
Phil Foden
"It's a shock to me because I know what Phil can do on a day-to-day basis. I know what Phil can do on a pitch at any given moment.
“Phil will probably say that he's not produced enough of what he can do on the field for Manchester City or not been given the chance to. Now, only Phil and Pep (Guardiola) know those answers. That's probably had a ripple effect into the decision that Thomas has made."
Harry Maguire
Maguire spoke on his omission earlier this week, stating: I was confident I could of played a major part this summer for my country after the season I’ve had. I’ve been left shocked and gutted by the decision" as he expressed his disappointment. Walker says him being left out was something he has to take on the chin.
“I think for what he's done this season, and especially where Manchester United are this season, you kind of thought that he'd have a good running to get into that squad.
"I think his experience being at all the tournaments that I've been at as well, you know, he's been a vital part of that. So, I think he's very unlucky not to get in that.
"I think he speaks very well of just how much playing for England means for him. So it's going to have been, you know, very tough for him to... well, a very tough pill for him to swallow yesterday in that phone conversation.
"But it's football and he has to deal with it, and he has to dust himself down and get on with it, really."
"He's fantastic and you can see that with how he plays for England, you know, he always steps up, even in penalties. I think I have to look at that.
Alexander Arnold
Lastly, Real Madrid's Trent Alexander-Arnold was left out of the side in a move that Walker says is unthinkable for a player featuring for the La Liga giants.
"I think if you were to say a player that plays for Real Madrid doesn't get into the England fold, it's kind of unheard of," Walker said.
On whether or not he can understand why Alexander-Arnold hasn't been included: "No, not really. But let's talk about what Trent does unbelievably well and probably the best in the world in his position at right-back with his range of passes, his delivery on the ball, his assists.
"And also, you have to think about the big games that he's played in, whether that's Champions League finals or big games for Liverpool, or big games for Real Madrid.
"You have to take that in consideration because as much as someone's a good player, when you get put on in a World Cup quarter-final, World Cup semi-final, a European Championship final, it takes a little bit of a personality to make sure that you can get through that game, not just by your ability, but also mentally as well."