Bradley has has not played for the Premier League giants since suffering a serious knee injury away at Arsenal in early January with that subsequently requiring surgery to repair ligament damage.
The right-back has been training alone over the summer, but he did join Andoni Iraola's squad for the preseason tour of USA.
His new club manager is cautious over his comeback and O'Neill admitted he's expected to miss the incoming UEFA Nations League games this autumn.
"Conor is where I expected him to be. I knew the injury was going to take longer than maybe some people were thinking.
"He's making good progress. It has to be managed very, very carefully, an injury of that nature. He's just become a dad as well, so he's got other things to worry about as well, so congratulations to him.
"Conor will be with us when he's ready and fit, and we'll be delighted to have him back. I'm comfortable with him waiting until 2027."
O'Neill's charges go to Georgia and host Hungary at the end of September before an away clash with Ukraine and a home tie with Georgia at the start of October.