Fraser enjoyed an impressive loan last season as he helped Saints to promotion back to the Premier League.
“I was always intending to come back, I was going to go nowhere else," he told the club's website. "It was here or nowhere. I made that decision from day one when I first came through these doors.
“When you step through the door, just meeting everyone. It's kind of like a family run club. So it's just that smile knowing you’re going in and you know you're going to be happy. I just think when you've got something like that, something so special, I think you do everything to try and keep a hold of it. So that's why from day one like I said, to come back. I was going nowhere else.
“So yeah, everything is done right at this club from top to bottom, and everyone's in the same boat going on the same journey, trying to be the best that we can be. And I think that's so exciting to be involved in.”
On getting his fitness up to speed, Fraser added: "I'll ask to play in any game that's available to try and get 45 minutes or so in the legs and days off that we might get, I'll just come in and just do extras, trying to gain what I've missed over the last few months.
"So it won't take me long, I think the experience of games helps me through times where I know what I need to get the best out of me in the games. So that'll be fine."