"More than anything, I feel terribly sorry that for various reasons I have kept my audience waiting for such a long time," Ueda told Edge in a new interview.
The Last Guardian has now been in development for more than half a decade after being formally announced in 2009, though Ueda said his creative contribution to the project was completed a "long time ago."
"The details of when, where, and how [The Last Guardian] will be completed are beyond my control," he said.
Ueda also briefly discussed his decision to leave Sony as a full-time employee, and instead work on The Last Guardian in a freelance capacity.
"It was not easy, but I can’t go into the details just yet," he said. "It will be good to be able to discuss it along with a post-mortem of The Last Guardian someday."
Sony president of Worldwide Studios Shuhei Yoshida said last month that the developer was "reengineering" The Last Guardian, though he would not say if the game was in development for PlayStation 3 or PlayStation 4.
The Last Guardian has made "slow progress" for years. Sony senior vice president of product development Scott Rohde said during E3 2012 that the game will ship "when it is absolutely ready." He also said Sony has no deadline whatsoever for the game.