But Johnson is expected to feature prominently in a tournament that has invigorated the league pre-season.
Most clubs have opted to rest their top-line players who took part in last year's World Cup as they manage their workload, but there was little doubt Johnson would play.
"Shaun just about knocked my door down wanting to play," Warriors coach Matt Elliott says.
He's even been named Warriors captain for the two-day tournament and the halfback has played a leading hand in helping put the Warriors' game plan together.
"I think my background will give me an advantage," Johnson says. "I am feeling a little more confident about the weekend than a lot of others. There's a lot more room than for a normal game. I think it will help and hopefully we can use some of the tools I used in touch.
"I want to win because this could really set the tone for the year so I will be doing anything and everything to try to give us that edge. It's going to be an awesome occasion. It's the unknown for everyone so I'm not sure one person can come in with more wisdom than others but in terms of making sure everyone is on the same page and not forcing it, letting things happen naturally, I think that's where I can really help out."
A look at a YouTube video of Johnson playing in the 2007 and 2008 national secondary school touch tournaments shows the game came naturally for him.
He played rugby for Orewa College 1st XV and also played league for Hibiscus Coast but touch was his first love and he saw himself going a long way in the game.
"It was the sport I liked the most, purely for the fact I was too small to play league," he says.
"The only thing that stopped me from playing touch is that it was never going to be a career. You could never make a living out of it. If it was a professional sport, who knows?
"It was awesome. I appreciate it a lot more now that I am in this position and I can look back and see what it's done for my game.
"I don't know if I would be here now if it wasn't for touch. It got me noticed, my step, my ball work. It all helped out."
He weighed just 68kg when he arrived at Mt Smart Stadium.
The Warriors took a patient approach with him, refusing to bow to calls for Johnson to play for the first-grade side until 2011, as he learned his trade and bulked up.
He's now 92kg but doesn't appear to have lost any of his speed or agility. The Warriors last weekend signed him to a new four-year deal which will see him remain at the club until at least the end of 2017.
A fortnight ago, Johnson played touch for the first time in about two years with his friends from school.
"I had so much fun," he says. "It was just like old times. We were calling all these touch moves we hadn't heard in so long and it brought back all these memories."
The difference from five years ago, however, was they were beaten. Johnson will hope his Kryptonite works better this weekend.
