After almost six years with the Gunners in the Premier League, Tierney will return to fight for another league title under manager Brendan Rogers who took no time in bringing him in for free. Celtic’s rush to resign Arsenal fullback Tierney who is just 28 years old comes as no surprise as the Scottish champions seek to improve their defense without splashing the cash.
Despite such an excellent piece of business, Nevin revealed his disappointment to see such a talented player go to waste in North London before leaving the English top flight altogether.
"The end to Kieran Tierney's Premier League career is one of the most confusing and disappointing things I've seen.
"As an all-round player, he was a better left-back than Andy Robertson. Andy has done some brilliant things with Liverpool but as a player, not when it comes to crossing, but in terms of getting forward, Kieran was just as good and adaptable.
“That's no disrespect to Andy Robertson, who I think is world-class, but for Kieran to have done nowhere near as much is just partially baffling and just disappointing.
"I don't think he's done anything particularly wrong other than getting injured which held him back."
Even though Nevin was frustrated with Tierney’s career path, he understands his decision to join Celtic who can offer him a stronger chance at silverware domestically and European football much like Arsenal.
"Anyway, he's swapping the substitutes' bench for the place he loves and a place where he can still play Champions League football.
"Celtic pushed Bayern Munich all the way in Europe last season. It's not that bad, is it?
"Did he underachieve? Yes, but it's not due to any fault of his own."