The Trinidad & Tobago striker was a target for Spurs during the January transfer window.
Jones decided to stay at the Stadium of Light and signed a new four-and-a-half year contract.
“If we’d have lost Kenwyne, and I’ll be honest with you, I thought I may as well have packed my bags and just gone,” said Sbragia.
“We had to keep him at the club and I’d love to keep him here for five, six or seven years because he is so important to us.
“After his injury, he’s come back and done extremely well by scoring lots of goals which is what we needed him to do.
“But we had to think about which way we were going as a club. Was it a case of just trying to survive another year or were we thinking long term?
“In the past, this club would probably have sold someone like Kenwyne, but we’re thinking long term now.
“That means keeping our best players and trying to bring in even better ones.”