The 30-year-old made 243 appearances for the Canaries, and was promoted to the Premier League twice.
"It's disappointing obviously, but I think the direction that the club needs to go, it's a rebuild in structure," Ruddy told BBC Radio Norfolk.
"For reasons other than football, it was a decision that was made."
Ruddy, whose final match for the club was their 4-0 win over QPR, continued: "The club did have the option on me, but mitigating circumstances within that contract meant that it was probably impossible for the club to uphold that.
"It was nice that we were told when we were and nice that I was able to go out in this manner on Sunday."
Ruddy joined Norwich from Everton in 2010, and as well as helping them reach the top flight twice, he was capped once by England in 2012.
But he is one of seven out-of-contract players to leave a club that failed to achieve an instant return to the Premier League and are currently without a permanent manager.
"Going back to when I was first here, Paul Lambert took what was a calculated risk, I'd say, of £250,000.
"You look back on that now, it's not an awful lot of money. I'm not sure you get too much goalkeeper for £250,000 these days," said Ruddy.
"I was grateful to him, to (majority shareholder) Delia Smith and (former chief executive) David McNally for allowing me to join the club, for the years after that, apart from this season and last season, have been superb.
"Four of the seven years here have been in the Premier League. It's been a special time in my life. I'm only 30 years old, I'm not retiring tomorrow.
"We move onto a new day, a new challenge and hopefully I've got 10 years left in me."

Saints have lost both games against the French side this season, 30-12 in front of their own fans in April and then 33-16 in June in the reverse fixture.
Catalans forward Willie Mason was released from his contract this week as he was out for the rest of the season with an ankle injury.
Half-back Lucas Albert replaces Thomas Bosc in their only change.
St Helens (from): Lomax, Turner, Percival, Swift, Walsh, Walmsley, Roby, Amor, Vea, Wilkin, McCarthy-Scarsbrook, Tasi, Richards, Thompson, Peyroux, Greenwood, Owens, Fleming, Knowles.
Catalans (from): Gigot, Broughton, Duport, Carney, Anderson, Aiton, Casty, Stewart, Horo, Baitieri, Taylor, Bousquet, Pelissier, Mounis, Elima, Yaha, Escare, Albert, Garcia.
Norwich City goalkeeper John Ruddy was "not massively" surprised about being released by the Championship club this summer after seven years.
[NEXT_CONCEPT]
St Helens have named an unchanged 19-man squad from the one that secured a narrow victory at Warrington.