Brees has been out for a few weeks as his team allowed him to rest following a minor oblique strain, with Saints coaches expecting him to play a part in their pre-season fixture on Saturday.
"Today was my first day to be full-go," said Brees, according to the NFL's official website.
"I've been taking it very slow. I wanted to make sure it was all good. I'm still not 100%, but I hope by Saturday I am."
The new NFL season is due to get underway next month.