Source: Team_Talk
Walton left out of Argyle squad
Walton became Argyle's record signing just last summer when he moved from QPR but enjoyed a troubled first season at Home Park.
The 21-year-old has played most of his football in midfield but has decided he sees his future as a central defender.
Sturrock said: "He wants to play centre-back and there are other players ahead of him at centre-back.
"Everybody was told that, performance wise, 22 players were going to get taken on the tour and Simon's been left behind.
"Simon and I have had a good discussion about his whole scenario here and I think it's vitally important that he appreciates the situation."
