But with Lions Test places up for grabs, Shaw can make strong claims this weekend, despite being initially overlooked for Sir Clive Woodward's 45-man squad.
After arriving in New Zealand as replacement for injured Irish second-row forward Malcolm O'Kelly a week ago, Shaw is looking to carry his Zurich Premiership form into the international arena after helping Wasps land their third successive league crown.
"I felt that I finished the tail-end of the season back home with a bang," he said.
"It is up to me now to show the rest of the guys that they were right to pick me - that's all I can do.
"It is going to be an immensely difficult game, the Maori are a quality side. I remember playing against them two years ago for England, and it was a really tricky fixture."
Shaw though, at least has time on his side to make an impact with the Lions, unlike during England's 2003 World Cup campaign when he travelled Down Under to take over from Danny Grewcock, but never featured in competitive action.
"It was difficult at the World Cup,' he added. "I was only there for the last three weeks, and the team was very much cemented by then.
"I've got more of a chance this time around, because it is still fairly early on in the tour.
"I guess with the few disappointments I've had in my career, I want to prove things to myself and everyone else who is watching."
Shaw will pack down behind the heaviest front-row in Lions history, with England trio Andrew Sheridan, Steve Thompson and Julian White tipping the scales at more than 54 stone.
The Lions' anticipated power game should suit Shaw, but he knows the main aim must be to see them produce a performance fitting for what has been described as an unofficial 'fourth Test'.
"You can have all the size and weight you want, but if you don't go out there with the right mindset and do what we said we were going to do in training, then it all counts for nothing," he said.