Meanwhile, running back Alvin Kamara will not play against the Cardinals.
Brees has been out since Sept. 15, when he suffered a torn ligament in the thumb on his passing hand as he made contact with the outstretched hand of Los Angeles Rams defensive lineman Aaron Donald. Dr. Steven Shin performed surgery on the thumb the following week in Los Angeles, and the expectation was that Brees would miss about six weeks.
The Saints had the option of letting Teddy Bridgewater make another start before the Week 9 bye. The Saints are undefeated in Bridgewater's five starts this season. But in a decision that reflects how much NFL coaches value every game and make no assumptions, the plan is for Brees to start.
"We have a good team," a source said. "No. 9 [Brees] makes us better."
Kamara, who missed last week's game at Chicago, had been listed as questionable after he practiced on a limited basis both Thursday and Friday with knee and ankle injuries. He is expected back after New Orleans' bye week, when the team hosts Atlanta on Nov. 10, sources said.
The Saints will again rely heavily on veteran backup Latavius Murray, who had 27 carries for 119 yards and two touchdowns last week, plus five catches for 31 yards.
With Brees, accuracy and ball security would be the most significant concerns. He returned to practice this week with the expectation of playing, and the emphasis will be on him getting the ball out quickly and trusting an offensive line that has proved to be among the best in the NFL.
Arizona's defense also leads the league with 12 forced fumbles. They have forced multiple fumbles in four games.
Brees, who did not appear to have any limitations on what he was able to do during the portions of practice that were open to the media this week, said on Wednesday that he just wanted to make sure that he was as comfortable, confident and accurate as he needs to be.
He said the decision would come down to "just making sure I can be me."
When Brees was asked if there is any greater risk of reinjury now than there would be two weeks from now, he seemed to suggest that is not a factor in the decision.
"I mean, listen, it's not fully healed I think until three months. But that internal brace obviously provides some stability and support, as does the splint," Brees said of both an internal brace that was installed when he had surgery to repair the torn ulnar collateral ligament on Sept. 18 and an external splint that he is likely to wear when he returns.
ESPN's Mike Triplett and Adam Schefter contributed to this report.