Marmion has looked at ease ever since making his GUINNESS PRO12 debut in the opening round of the 2012/13 season.
Remarkably the Connacht academy product went on to start every PRO12 game in that campaign, the only player in the league to do so - and he has barely been out of the team since.
It did not take long for him to gain recognition on the senior international stage, having already impressed for Ireland Under-20s at the 2011 and 2012 IRB Junior World Championship.
And after being named in several squads, Joe Schmidt gave Marmion his first senior cap in the 2014 end-of-season Test against Argentina.
Ultimately he missed out on selection for the Rugby World Cup by a narrow margin but he has not let that affect a strong start to the season - scoring a try in victories over Cardiff Blues and Zebre.
Indeed, if Connacht are to keep up their strong pace the whole way through this year's GUINNESS PRO12, Marmion's form and fitness will be imperative.
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