Brees played through an injured right foot - reportedly a torn plantar fascia - in a 35-27 loss to Detroit on Monday and has gone through examinations this week. He threw for three touchdowns and 341 yards to surpass 4,000 for an NFL-record 10th consecutive season.
"We're kind of taking it day by day," Payton said. "Each day we'll gather more information and have a better idea of where he will be as it pertains to playing."
Having been eliminated from the playoff race, the Saints (5-9) might have their eyes on getting Brees healthy for his 16th NFL season. There is a small matter of pride, however, in avoiding double-digit losses for the first time in Payton's nine campaigns.
New Orleans went 7-9 in 2014 to match Payton's worst showing since joining the team following a 3-13 finish in 2005.
Matt Flynn would likely take over if Brees can't go with third-round draft pick Garrett Grayson as his backup. Flynn has totaled 2,541 passing yards and 17 touchdowns with 11 interceptions in 51 games (seven starts), but he and Grayson haven't taken a snap this season.
Brees has missed one game because of injury in 10 seasons with the Saints, a 27-22 loss in Carolina on Sept. 27. The now-injured Luke McCown (back) went 31 of 38 for 310 yards in his place.
"He is usually pretty reliable, so the idea is that we'll just go through the week and see if he is going to be up or not," tight end Ben Watson said.
Bortles, meanwhile, will seek to add a share of another Jaguars single-season record while keeping his team's faint playoff hopes alive. Jacksonville (5-9) trails AFC South leader Houston by two games and will visit the Texans for its regular-season finale Jan. 3.
The Jaguars are also trying to reach six wins for the first time since going 8-8 in 2010.
"There's a fighting chance to be in the playoffs, so it's not like we're really looking at the offseason," defensive end Jared Odrick told the team's official website. "We're still thinking about, 'What are our chances, what are our options, what are the things that need to happen for us to make the playoffs?' The more we think like that, the better chance we do have."
The Jaguars failed to boost their hopes last weekend by losing 23-17 to Atlanta after routing division rival Indianapolis 51-16 the previous week. Bortles just missed matching Mark Brunell's 1996 team mark for 300-yard passing performances in one season of six by finishing with 297.
He had one touchdown and one interception after throwing eight TDs with no picks in the previous two games. Bortles has already set the franchise's single-season record with 31 touchdowns.
"If you go back and look at the first game to now where he is at, I think he has more ownership of the offense and there is a certain comfort level," coach Gus Bradley said.
Bortles and his top receiver Allen Robinson were left off the Pro Bowl roster announced Tuesday with Robinson named a first alternate despite being one of the league leaders with 13 touchdown catches.
With 1,141 yards, he's the Jaguars' first receiver to top 1,000 since Jimmy Smith in 2005.
"I think he's way more deserving than to be the first alternate for sure," Bortles said. "I think he belongs in that list of guys. But credit to him. That's a special honor and privilege. Happy for him and excited for him, and definitely well deserved."
The Saints have won their past two games against Jacksonville, and Brees threw for 445 yards in the most recent matchup in New Orleans, a 41-24 win in 2007. He had 351 yards in a 23-10 road win four years ago.