Smyth informed Bann coach Suzanne Evans that he would not be available this season following his selection for the Down GAA Development Squad.
He has been involved with the first team set-up since he was 15 and had captained Banbridge Academy's McCullough Cup squad, which they were unfortunate to lose on penalty strokes after Smyth himself had scored twice as the game finished 4-4.
'Moppy' had also represented Ireland at various junior levels throughout the game.
Team Manager Paddy Grimes said he was "gutted" that Bann would be losing one of their rising stars.
"Matthew attended our first training session but then wasn't at the next one. He then contacted Suzanne and told her what was happening," Grimes said.
"It's a huge blow for us and for Suzanne especially as it is her second season in charge and all the players knew where they stood, what their positions were and what the plans were for this season.
"He had a disappointing end to the season last term as it was cut short due to injury but we were hoping that would act as an impetus for him to push on for this coming season.
"You don't get many six foot players as skillful as Moppy and we're sad to be losing him. But on the other hand it provides an opportunity for one of our younger players to push through into the squad."
However, Grimes conceeded that while it was a shock for Bann, for Smyth gaelic was always a big part of his life.
"Gaelic was always Matthew's first love and his parents would have been very keen for him to get involved in it so when this opportunity came to pass it was no big surprise that he took it," he said.
"But we wish him all the best for the future and hope that everything works out well for him."