It is hard to imagine the new one can be as bad as the old, but you never know.
During his time away - running unfamiliar lines and following strange new orders barked out in equally unfamiliar accents as a budding NFL draftee - Wales played 18 Test matches and lost 17 of them.
Rees-Zammit insists that decline wasn’t down to effort or attitude, but something more fundamental: the sudden loss of experience that followed the 2023 World Cup.
“I don’t think anyone really expected what happened, to be honest,” he reflects.
“A lot of big names left after the World Cup. A lot of experience left. Those boys coming through had a chance to pull on the jersey straight away.
“When I left, I was thinking about trying to make it in the NFL. I didn’t really think too much about what was going to go on.
“It was a tough period. But now is the only time we can change. We’ve got a great coaching staff in Steve (Tandy) and everyone else.
“Now is the time to change. All the boys are excited to do so. We’re ready to create this new identity and really give back to the Welsh fans.”
This, then, is year zero - the planting of hopeful new seeds after a rugby apocalypse.
Amid the wastelands, Rees-Zammit is viewed as the cream of a thin crop when it comes to match-winning potential and marketing credibility for the beleaguered Welsh Rugby Union.
In short, there’s a lot on those broad shoulders, made broader and more muscular after his spell with the Kansas City Chiefs and Jacksonville Jaguars.
“The boys are really excited,” insists the Bristol Bears star.
“We showed glimpses of what we can do last weekend. I don’t think the scoreline reflected the moments we had in the game.
“Maybe there were just a couple of lapses of concentration, he says of the 52-28 defeat to the Pumas.
“That’s going to come. We’re trying to create a foundation to show an identity we can build on. The vibes in camp are really high.
“Everyone’s locked in on what’s next. Japan will be a tough game but everyone is raring to go. Everyone is buying in 100 per cent. We’re all ready.”
For a 24-year-old who’s already packed in an NFL adventure, 33 caps, and a Lions tour, Rees-Zammit now finds himself in the role of experienced old-timer.
But when he ran out at the Principality Stadium last week as a replacement against Argentina, the roar that greeted him made him realise just how much he had missed it.
“It was a great experience,” he says.
“I did really miss being able to play at the Principality in front of our fans. It was incredible.
“When I came on and heard the crowd – all the support I had, it meant so much to me. I’m very grateful to the support of my coaches, team-mates and the fans who came to watch me and Wales play. It was a great feeling.”
Rees-Zammit calls it his “happy place” — fitting for a player who grew up just ten minutes from the stadium.
“It probably made it that extra special to be honest, being away for two years,” he says.
“It felt like a long time, but also felt like I left yesterday. When I got to put that jersey on and then came on, it felt really good. That was why I said it’s my happy place.
READ MORE: Steve Tandy Insists Progress Will Come Despite Wales’ Humbling Record Defeat to Argentina
“I grew up in Cardiff, just 10 minutes away from the stadium. I previously won 32 caps for my country. It felt really good to get another cap in front of all our fans.”
After five weeks out with injury, Rees-Zammit insists he’s “fit and ready to go” for Japan.
He also says he has returned from his NFL stint in better physical condition than ever before.
“I mean, I’m heavier. I’m more built upper-body. I’m quicker,” he says.
“It’s a tough question to answer because it depends on scenarios of me having to go flat out with sprinting.
“But in terms of my weight, I’m now just over 100kgs. I’m feeling good and fast at that weight. I’m definitely heavier, but I’m also faster.”
And he believes that his time in the United States has given him a new dimension to his game.
“There’s definitely a lot that I’ve brought in that I’ve learned out there. I’m a lot more explosive - a lot more physical.
Both defensively and when I have ball in hand, I feel I have a different game to what I had before, with my physicality.
“The more I get the ball in my hands, the more I’ll be able to show that.”
The NFL experience didn’t just make him stronger; it also gave him a fresh view on sport, celebrity, and the power of personality.
“It’s a lot different out in America,” he says. “Those stars are global.
“They push their sport through their players. It’s something in rugby that isn’t done as much.
“Maybe that’s just because the game isn’t as global as American football. The NFL is based in America, but the stars and the personalities are worldwide.
“It’s just about how we grow the game of rugby. Whether that’s the sport itself or getting stars within it to grow it.”
Rees-Zammit, who has long been one of Welsh rugby’s most marketable players, doesn’t shy away from that role.
“That’s one of the main reasons I play the game, is to try and inspire others to play the game,” he says.
“Just playing the game for the love of it, just playing the way I play, exciting rugby and trying to create things. That hopefully leads to kids wanting to get involved and do the same thing.”
“I don’t really see it as pressure to be honest. I’m living my dream,.
