That's why he is such a big fan of American Football - his favourite player is receiver Wes Welker, who plays for his favourite team the Patriots.
Welker, currently leading the NFL in receiving yards is, like Mathewson, relatively short. In fact, Welker, who stands 1.75m (to Mathewson's 1.79m), bears a remarkable resemblance to the 26-year-old former Blues and soon-to-be former Auckland halfback.
Which begs the question, why is Mathewson leaving New Zealand for the relative rugby backwater of Perth's Western Force, and just as he is exerting his dominance over long-time rival Piri Weepu?
While Mathewson prepares for tomorrow night's ITM Cup premiership final against Canterbury in Christchurch, All Black Weepu is on a family holiday in Taupo - not wanted by coach Wayne Pivac for the competition showpiece.
And yet, there are no regrets for Mathewson as he reflects on a tumultuous year, which began with the seemingly endless shambles of the Blues' season and which could finish on a high at AMI Stadium.
"The environment that this team has created has made it really enjoyable," he says.
"They are a good bunch of guys, the management are great. Everyone gets on well and the game plan is simple. That's the pleasing thing, coming from the Blues in the Super season.
"[But] I'm looking forward to going. I have no regrets about leaving. As you see, there are still a lot of issues going on with [the Blues] picking their squad and that sort of thing so I'm looking forward to moving on."
There is no doubt that the Blues' problems are continuing as coach Sir John Kirwan picks up the pieces of the past regime and attempts to get to grips with a player-trading system which he admits he has found difficult to understand.
The departure of Tony Woodcock and Ma'a Nonu leaves big holes but so will Mathewson's decision to go. He earned four test caps for the All Blacks and would be the ideal man to keep Weepu honest next year, as he has so often in the past.
Mathewson adds: "The main reason was the Super stuff and game time, that was the main reason for moving."
His battles with Weepu last season with the Blues started at Wellington and the Hurricanes. A year after moved north in search of more game time, Weepu followed. It has been an interesting relationship.
"We get on really well. I would prefer it if we were rivals in different teams. Instead, we're rivals in the same team. But it's quite a weird situation. He always gets flak about the condition he comes in at and I usually get to start then come the second half of the season he gets to play.
"It's been good for both of us, I feel. Competition is healthy, it's pushed both of us."
Talking about the pressure of expectation ahead of his move to the Western Force, to which Mathewson has signed as a "marquee player", he says: "I'm too competitive to go there and cruise for a year or two. The pressure is coming from me and it will come from the outside there. They are expecting big things and I wouldn't expect anything else.
"I'm 26, that's still young. If I play there for a year or two I'll still only be 28. I haven't had any injuries, so there's no reason why I couldn't come back.
"I still feel I could offer New Zealand a lot and that's one of the disappointing things about leaving. But in saying that, I'm still in the Super competition, which is tough. I didn't want to go to Europe, I wanted to stay in this competition which suits my style."
Expanding on the "disappointing" aspect, Mathewson says: "Everyone talks about these good young halfbacks coming through, but without sounding arrogant, I still feel like I can mix it with them.
"I guess everyone is looking at the Super campaign in which every Blues player was disappointing. I guess that's what sticks in people's memories."
Now he is preparing to go to Nib Stadium and a city more known for its weather than rugby. In terms of atmosphere at the sunbaked ground, it's a long way from Wembley Stadium, where he watched the 49ers play the Broncos on an All Blacks' tour in 2010, or even the new AMI Stadium for that matter.
But, the avid follower of what is in New Zealand an unfashionable sport is clearly not scared of trying new things.
There's probably not much chance of Weepu following him there, either.
