But the prop believes he is now in a better position to deliver what he knows he can during this campaign.
Waller returned to boyhood club Saints in the summer of 2022, coming back from Worcester Warriors.
He had spent five seasons at Sixways but initially came through the Saints Academy system and made his debut for the black, green and gold in 2012.
Waller was a regular in the first-team squad during the memorable double-winning campaign of 2013/14, making 15 Premiership appearances and winning the young player of the season award.
He played 95 times during his first stint with Saints, but departed for Sixways in 2017 in search of more game time and notched up more than 100 appearances for Worcester.
He eventually made the move back to Northampton last year but endured a difficult campaign, making four starts and 13 appearances from the bench.
"It's been nice for me to be home but last year was a frustrating one for me because I probably put a lot of pressure on myself and didn't really play any of the rugby that I know I'm capable of," Waller said.
"This season, coming back from a shoulder operation, it's been nice that I've had a lot of time to sit and reflect and look at what I can do better to make sure it's the best version of me on the pitch.
"It was a good start last week and hopefully I can continue building on that myself and hopefully there will be a few more performances of me at my best this year.
"Looking back on it, it was probably a bit subconscious.
"At the start of the year, I got concussed and then was in and out of the squad, not playing particularly often.
"In my head, I probably thought it would be an easier transition than it was.
"I was putting a lot of pressure on myself when I played to be absolutely perfect and we all know the game of rugby isn't perfect, let alone any person.
"So this year, it's very much a case of me knowing I play my best rugby when I'm enjoying myself, when I'm relaxed and that doesn't mean I don't do my job and the things that are required of me, but it does mean I put less pressure on myself and go out there to be the best version of myself."
Waller made his first appearance of the new season last Saturday, starting in the 55-5 Premiership Rugby Cup pool stage win against Cambridge Rugby at cinch Stadium at Franklin's Gardens.
And he said: "It's been quite nice because it's been a good build through these past few games.
"We're putting layer upon layer of the way we want to play and clearly there were some disappointing moments in the first few matches but it's the first few hit-outs, a young squad, a lot of whom need game time because it's a long first block until the end of January.
"We're going to need a full squad effort so for everyone to have had some game time under their belt is going to be invaluable.
"It's about building more and more, and it's another level up this weekend as we go down to Bristol."
On the challenge of facing the Bears at Ashton Gate in Saturday's cup clash, Waller said: "It's a lovely ground and the fans there are always pretty lively and pretty hostile.
"They play a pretty exciting brand of rugby and they like to throw the ball around.
"For us, it's a good test of our defence because we've had a lot of work on that.
"Clearly last year that was an area we needed to get better at so it's an area we've put a lot of focus on in pre-season and hopefully this is going to be a real good test for us against Bristol who enjoy stressing defences."
Waller was part of a Saints side that blended youth with experience once again last weekend.
And over the years he has moved from the former category to the latter.
"It's weird because you don't really notice it until you become the old player," Waller said.
"I was in a session the other day and I was the oldest one out there, which was pretty humbling.
"There are obviously some improvements compared to when I was young here.
"We're hugely driven on improvement and it's about everyone getting better in every scenario.
"You look at all the internationals we've got and they're still constantly striving to improve, which is massive because it drives standards for everyone from one to 50 in the squad.
"The desire to be better every week is something I've enjoyed since I've been back."