Brees suffered the rib injury against the 49ers on Sunday.
The Saints are preparing for quarterback Drew Brees to miss time after suffering a rib contusion in Sunday's win over the 49ers, according to NFL Network's Ian Rapoport.
Rapoport reports Brees, 41, could be out for some time in order to fully heal from the rib injury, which he sustained midway through the second quarter. Brees took a sack from Kentavius Street and remained in the game. He informed coaches at halftime that he was unable to continue.
After Sunday's game, coach Sean Payton said Brees would undergo an MRI and X-rays to assess the severity of the injury.
"He took a heavy shot in the first half. As he came out in the second half, he felt it was really impacting him," Payton told reporters. "As he tried to throw, he just came up to me and said, 'Hey, I don't feel like I'm capable of playing.' And so, quickly, we made the switch and, you know, that happens sometimes.
"He felt strong enough about letting me know and I know when he does that, which is probably gonna be the first time in 15 years, that it was significant enough where he felt like he couldn't function in the second half."
According to Rapoport, Brees will undergo an MRI on Monday for cartilage damage.
Brees was 8-for-13 for 76 yards and a touchdown before leaving the game.
"I was not going to be able to be effective," Brees said of the injury. "It had nothing to do with pain. It was simply just what my body was going to be able to do or not be able to do."
Brees was replaced by Jameis Winston, who went 6-for-10 for 63 yards. Taysom Hill also took snaps at quarterback but did not attempt a pass in the second half. The Saints beat the 49ers 27–13.