Brees injured the foot during the Saints' 35-27 loss to the Detroit Lions on Monday night. An MRI on Tuesday confirmed the injury, according to multiple reports.
The foot injury is similar to the one that has sidelined Denver Broncos quarterback Peyton Manning for the past five weeks. ESPN.com reported that Brees is seeking the advice of the doctor who treated Manning.
The 36-year-old Brees was hurt during the second quarter on Monday night while avoiding defensive pressure, but he returned to throw three touchdown passes in the second half.
The Saints play the Jacksonville Jaguars at home on Sunday. Brees is expected to be listed as day to day for that game. If Brees is unable to play, his backups are Matt Flynn and rookie Garrett Grayson.
Brees had never missed a game because of injury in his 16-year NFL career before this season until he sat out Week 3 against the Carolina Panthers with an ailing shoulder.
The veteran has thrown for 4,135 yards with 28 touchdowns and 11 interceptions this season.