The RBS 6 Nations player of the tournament nominee gave serious consideration to joining the Aviva Premiership club in 2007.
Frustrated by his lack of opportunity at Munster, he felt he needed to escape the shadow of Lions second rows Paul O'Connell and Donncha O'Callaghan.
But the inevitable impact a move overseas would have on his international prospects compelled him to stay at Thomond Park.
The 28-year-old's loyalty is now being rewarded with his fourth Test start and man-of-the-match display in Saturday's 32-14 rout of Scotland likely to have secured him an extended run in the team.
"I went to Northampton and met (coach) Dorian West and (director of rugby) Jim Mallinder. They were lovely people and it was a great club," he said.
"The first thing they asked me to do was to go on the weighing scales because on Munster's website my weight was 89kg! You're not much of second row if you weigh 89kg!
"It was obviously a frustrating time because all I wanted to do was play.
"But I changed tack, moved into the back row and I learned a lot there.
"I'd be lying if I said I didn't contemplate moving, but I'm glad now that I didn't.
"There'd be days when you'd be tearing your hair out that you didn't move, but now after starting for your country, I'm thrilled to bits.
"What made up made up mind was the impact going abroad would have on my international opportunities."
Ryan, who starts Saturday's clash with England at Twickenham, yesterday agreed a new two-year contract with Munster.
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